2002

Thursday, 9 January 2003

Summary

Numerous extreme events and El Niño returns Low rainfall in Bay of Plenty; Marlborough and Nelson cool inland Mild in Waikato and the northern South Island Average or above average sunshine

The past year will be remembered for its high number of severe weather events and climate extremes, according to Senior Climate Scientist Dr Jim Salinger of NIWA. Overall, 2002 featured many new climate records and weather extremes. Analysis of the year’s climate showed new records being set in many months for rainfall, temperature, and other climate extremes. It was also very dry in Bay of Plenty, Nelson, Marlborough and North Otago.

One of the most notable severe weather events was the worst snowfall for many years in mid-Canterbury and inland Otago during June, leaving hundreds of travellers stranded, and thousands of homes without power. A few days later, the “weather bomb” brought high winds, intense rainfall and flooding in many northern and western areas, being especially severe over the Coromandel Peninsula. In July the Waikato River overflowed at Mercer, flooding many nearby farms already saturated by weeks of wet weather.

“For the year, there were at least a dozen heavy rainfall/flood-producing events. A high number of gale-force southerly wind events also featured, with huge seas in Cook Strait or along eastern coastal regions, and there were also at least five tornadoes reported”, said Dr Salinger. “There were also three periods with snow to low levels in parts of the South Island in late autumn and winter, followed by damaging spring frosts in some eastern areas. At least five severe hailstorms – two with hailstones the size of golf balls – blitzed fruit crops, and significant soil moisture deficits had developed by the end of the year in the east of the South Island. Not a month went by without something of note”.

Lower than average pressures occurred southeast of the Chatham Islands with many more lows there than usual. This brought more frequent stronger changeable westerly and south-westerly winds over the North Island, and southerlies and south-westerlies over the South Island. Seas around New Zealand were warmer than normal until October. NIWA analyses of month-by-month records show:

• The year’s national average temperature was 12.5°C (the same as the 1961–1990 normal).
• The highest annual mean temperature recorded for the year was 16.2°C, recorded at Mokohinau Island.
• The highest recorded extreme air temperature for the year was 36.5°C, recorded at Darfield on 31 December, and the lowest –19.1°C (a new record low for June) at Tara Hills on the morning of 20 June.
• The 3rd warmest June on record for New Zealand overall occurred.
• February was the coolest since 1993. October was the coldest in 20 years.
• The driest recorded centre was Alexandra in Central Otago with 371 mm of rain for the year.
• Dunedin was the driest of the four main centres with 647 mm, and Wellington the wettest with 1250 mm. Auckland received 1075 mm and Christchurch 785 mm.
• Of the regularly reporting gauges, the Doon River gauge in Fiordland recorded the highest rainfall with an annual total of 8719 mm, followed by North Egmont with 6895 mm. Milford Sound was close with 6835 mm.
• Christchurch was the sunniest of the three largest centres with 2166 sunshine hours, followed by Wellington (2107 hours), and Auckland (2034 hours). Nelson was the sunniest centre in 2002 with 2580 hours, followed by Blenheim with 2534 hours. Tauranga recorded 2501 hours, well above average.
• Taumarunui had only 27 hours of bright sunshine in June (a New Zealand record low for June).
• Record high October sunshine throughout much of New Zealand.
• The highest recorded wind gust for the year was 183 km/h at Cape Reinga on 22 July.
• Thunderstorms were very common in January, occurring somewhere in New Zealand on 22 days of the month.

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.

For more details read on

2002 – Numerous Extreme Events Low rainfall in Bay of Plenty, Marlborough and Nelson Cool in some inland areas, mild in Waikato and the northern South Island Average or above average sunshine everywhere

Overall, more ‘lows’ (depressions) over and east of the Chatham Islands than usual gave many areas in New Zealand a rather changeable windy year with many climate extremes. Neutral conditions in the tropical Pacific occurred from January to April, whilst seas around New Zealand remained warmer than normal. This period was dominated by below average pressures over the North Island and northern South Island, while above average pressures prevailed over the Southern Ocean, often centred south of Tasmania. Easterly airflow anomalies occurred over the lower South Island. The period from May to December was largely influenced by the El Niño, being dominated by well below average pressures east of the Chatham Islands. Slightly above average pressures occurred in the north Tasman Sea. This pattern resulted in windier conditions with persistent westerly and south-westerly winds predominating over New Zealand. Seas cooled in spring with temperatures trending below average by November.

Rainfall in 2002 was well below normal in Bay of Plenty, with totals less than 70 percent of average. Rainfall was also below average in eastern Northland, Waikato, southern Waiarapa, Nelson and Marlborough. Significant soil moisture deficits had developed in Northland, Bay of Plenty, eastern Malrborough, south Canterbury and North Otago by the end of the year. It was wetter than average in Wanganui, coastal Southland, Fiordland, and the area near and about Christchurch.

The 2002 national average temperature, calculated by NIWA was 12.5°C, which was the same as the 1961–90 average. For New Zealand as a whole, there were five warmer than average months (May, June, August, September and December), of which June was exceptionally mild, contrasted by three cooler than average months (February, October and November). February and October were much cooler than usual. Temperatures were above average in Waikato, central Marlborough and Nelson for the year as a whole, but below average in King Country and in some inland South Island areas from Marlborough to Southland. The year was sunnier than normal overall in the eastern North Island, Nelson, Buller, Westland, and Southland.

Low rainfall in Bay of Plenty, Marlborough and Nelson

Rainfall in 2002 was well below normal in Bay of Plenty with totals less than 70 percent of average. Rainfall was also below average in eastern Northland, Waikato, southern Wairarapa, Nelson, and Marlborough. Rainfall was above average in Wanganui, coastal Southland, Fiordland, and the area near and about Christchurch, with totals exceeding 110 percent of average. Extremes of annual rainfall for the year 2002 were measured at:

Location	2002 rainfall (mm)	Percentage of normal	Year records began	Comments
Tauranga Airport	747	58	1898	3rd lowest
Whakatane Airport	790	68	1975	2nd lowest
Rotorua Airport	959	66	1899	2nd Lowest
Blenheim Airport	529	73	1941	3rd lowest

Of the four main centres, Dunedin was the driest with 647 mm and Wellington the wettest with 1250 mm. Auckland received 1075 mm and Christchurch 785 mm. Alexandra in Central Otago, was the driest location NIWA measured rainfall at in New Zealand, with only 371 mm. Of the regularly reporting rainfall stations for which rainfall data are presently available, the Doon River gauge, Middle Arm of Lake Te Anau in Fiordland (operated by Meridian Energy Ltd), recorded the highest rainfall in 2002 with an annual total of 8719 mm, followed by North Egmont with 6895 mm. In comparison, Milford Sound received 6835 mm.

Mild in Waikato and the northern South Island, cool in some inland areas

The 2002 national average temperature, calculated by NIWA, was 12.5°C, which was equal to the 1961–90 average. For New Zealand as a whole, there were five warmer than average months (May, June, August, September and December), of which June was exceptionally mild, contrasted by three cooler than average months (February, October and November), February and October being much cooler than average. 2002 mean temperatures ranged from 0.3 to 0.6°C above average in much of Waikato, central Marlborough and Nelson for the year as a whole, but 0.3 to 0.6°C below average in King Country, and some inland South Island areas from Marlborough to Southland. The warmest locale overall was Mokohinau Island, with a mean temperature for the year of 16.2°C.

Average or above average sunshine everywhere

The year was sunnier than normal in Bay of Plenty, the eastern North Island, Nelson, Buller, Westland, and Southland, with totals ranging from 105 to 110 percent of normal. Near average sunshine hours occurred in all other regions. Nelson was the sunniest centre in 2002, recording 2580 hours, followed by Blenheim with 2534 hours. Tauranga recorded 2501 hours, 9 percent above average. Total sunshine hours for the year 2002 in selected main centres were:

Location	2002 sunshine (hours)	Normal (hours)	Departure from normal	Comments
Auckland	2034	2008	+1%	Near average
Wellington	2107	2048	+3%	Near average
Christchurch	2166	2057	+5%	Above average
Invercargill	1705	1565	+9%	Above average

Significant Weather and Climate Events – 2002

Five warm months, three cooler

Of the five warmer than average months, June was exceptionally mild, and of the three cooler than average months, February and October were much cooler than normal.

3rd warmest June on record overall, with record-breaking low air temperature on 20 June

In spite of the weather extremes of heavy snowfall and severe frost in the South Island, June was about as warm as it gets at that time of year on the basis of historical records going back to the early 1850s. The national average mean temperature of 9.8 °C was 1.5 °C above normal – only June 1916 and 1971 were warmer. It was extremely mild in the North Island. The majority of the North Island sites from which temperature measurements are available experienced either their warmest or second warmest June on record. In Napier there were six almost summer-like days between 8 and 18 June when temperatures exceeded 20.0°C (five more than average). Although it was also warmer than usual over much of the South Island, it was very cold in eastern regions from the 15th to the 22nd, during which time the lowest air temperature for the month, which was –19.1°C, was recorded at Tara Hills, Omarama on the 20th. This is the lowest June air temperature on record at Tara Hills in measurements that commenced in 1950, as well as breaking the previous New Zealand June record of –15.6°C set at Tekapo in 1927 and Manorburn Dam in 1941.

Coolest February since 1993

February was much cooler than usual with mean temperatures at least 1.0°C below normal in many areas, especially in the east from Gisborne to Otago. The national average temperature of 16.2°C was 0.8°C below normal, and the lowest for February since 15.1°C in 1993. There were few very hot days.

Coldest October since 1982

The normal spring warming was absent in October, due to the frequent south-westerlies and also frequent clear cold nights. The national average temperature of 11.0°C (1.1°C below normal) was the lowest for October since 1982. It was particularly cold, with temperatures more than 2.0°C below normal in parts of King Country, and inland Wanganui.

Unusually high mean monthly temperatures in 2002 were recorded at:

Location	Mean temperature	Departure (°C)	Records began	Comments
June
Kaitaia Observatory	14.5	+1.8	1942	Highest
Whangarei Airport	14.3	+2.1	1968	Highest
Warkworth	13.5	+2.4	1972	Highest
Auckland, Henderson	13.6	+2.8	1986	Highest
Auckland, Owairaka	14.0	+2.6	1949	Highest
Auckland, Mangere	13.4	+2.0	1863	2nd highest
Auckland Airport	13.8	+2.5	1962	Highest
Paeroa	13.2	+3.3	1947	Highest
Tauranga Airport	12.9	+2.6	1913	Highest
Auckland, Owairaka	14.0	+2.6	1949	Highest
Whakatane Airport	11.3	+2.0	1975	Highest
Rotorua Airport	10.5	+2.2	1886	Highest
Taupo Airport	9.8	+2.6	1976	Highest
Pukekohe	13.3	+2.5	1971	Highest
Hamilton, Ruakura	12.7	+3.5	1907	Highest
Hamilton Airport	12.0	+2.7	1971	Highest
Taupo Airport	9.8	+2.6	1976	Highest
Pukekohe	13.3	+2.5	1971	Highest
New Plymouth Airport	12.8	+2.7	1944	Highest
Turangi	9.5	+2.3	1968	Highest
East Taratahi	9.9	+2.4	1906	2nd highest
Gisborne Airport	12.4	+2.5	1905	Equal highest
Napier Airport	11.8	+2.3	1974	Highest
Napier, Nelson Park	12.3	+2.7	1870	2nd highest
Turangi	9.5	+2.3	1968	Highest
Paraparaumu Airport	11.4	+2.2	1949	Highest
Palmerston North Airport	10.9	+2.4	1962	2nd highest
Wellington, Kelburn	10.9	+1.6	1863	2nd equal highest
Wellington Airport	12.2	+2.1	1962	Highest
Wallaceville	10.5	+2.2	1940	Highest
Normanby	12.0	+2.6	1977	Highest
Wanganui, Spriggens Pk	12.4	+2.4	1937	Highest
Takaka, Kotinga	10.5	+2.1	1986	Highest
Farewell Spit	12.5	+2.7	1971	Highest
Wallaceville	10.5	+2.2	1940	Highest
Nelson Airport	10.4	+3.0	1943	Highest
Blenheim Research	10.5	+2.7	1932	Highest
Blenheim Airport	9.5	+2.0	1941	Equal highest
September
Kaikoura	12.1	+2.0	1964	Equal highest
Christchurch Gardens	12.0	+2.0	1864	Equal highest
Dunedin, Musselburgh	11.1	+1.8	1947	Highest

Extraordinary high mean daily maximum temperatures were recorded at:

Location	Mean temperature	Departure (°C)	Records began	Comments
September
Napier, Nelson Park	19.5	+2.8	1870	Highest
Hanmer Forest	17.0	+2.9	1906	3rd highest
Kaikoura	16.3	+2.8	1964	Highest
Christchurch Gardens	18.1	+3.2	1864	Highest
Winchmore	16.7	+2.7	1950	Equal highest
Timaru Airport	17.1	+2.9	1962	Highest
Dunedin, Musselburgh	15.9	+3.0	1947	Highest

Extremely high maximum temperatures were recorded at:

Location	Maximum temperature (°C)	Records began	Date of occurrence	Comments
May
Gisborne Airport	26.1	1905	4	Highest
Kaikoura	25.6	1964	4	2nd highest
Winchmore	26.9	1950	4	Highest
Darfield	26.6	1939	4	2nd highest
Christchurch Gardens	27.2	1864	4	Highest
Lincoln	27.1	1881	4	3rd highest
Timaru Airport	26.1	1962	4	Highest
Waimate	26.5	1908	4	2nd highest
Oamaru Airport	26.1	1968	4	Highest
Clyde	26.0	1983	4	Highest
August
Whangarei Airport	20.8	1939	4	Highest
Darfield	23.3	1939	12	Highest
Christchurch Gardens	22.8	1864	12	2nd highest
Christchurch Airport	22.2	1954	12	2nd highest
Lincoln	21.6	1881	12	4th highest
Woodbury	23.0	1993	12	Highest
November
Murchison	30.1	1970	30	Highest

Unusually low mean monthly temperatures were recorded at:

Location	Mean temperature	Departure (°C)	Records began	Comments
February
Whakatu	16.1	–2.0	1930	2nd equal lowest
Appleby	15.7	–1.9	1932	3rd lowest
Blenheim	15.9	–2.0	1933	2nd equal lowest
Blenheim Airport	16.1	–2.4	1941	2nd lowest
Kaikoura	14.5	–1.9	1964	2nd lowest
Christchurch Airport	14.9	–1.8	1954	2nd lowest
October
Paeroa	12.2	–1.8	1947	2nd equal lowest
Rotorua Airport	10.4	–1.7	1964	Equal lowest
Taumarunui	10.5	–2.3	1947	2nd lowest
Chateau, Ruapehu	4.5	–2.1	1932	3rd equal lowest
Christchurch Airport	9.9	–2.0	1953	3rd lowest
Ettrick	9.5	–1.8	1985	Lowest
Gore	8.2	–1.7	1971	Lowest
November
Paeroa	14.1	–1.9	1947	2nd equal lowest
Taumarunui	12.4	–2.5	1947	Equal lowest
Gore	9.4	–2.3	1972	Lowest

Extraordinary low mean daily minimum temperatures were recorded at:

Location	Mean daily minimum temperature	Departure (°C)	Records began	Comments
October
Henderson, Auckland	7.2	–3.1	1986	Lowest
Rotorua Airport	5.1	–2.5	1964	Lowest
Taumarunui	4.7	–2.7	1947	Lowest
Blenheim Airport	4.3	–2.4	1941	Lowest
Hanmer Forest	1.7	–2.5	1906	3rd lowest
Christchurch Airport	3.5	–2.9	1953	Lowest
Timaru Airport	2.8	–2.1	1962	2nd lowest

Severe frost

There were a number of periods during the year with severe or damaging frosts.

20 June

The lowest air temperature for the year was a frigid –19.1°C recorded at Tara Hills, Omarama. This is the lowest June air temperature on record at Tara Hills in measurements that commenced in 1950, as well as breaking the previous all-time New Zealand June record of –15.6°C set at Tekapo in 1927 and Manorburn Dam in 1941.

26 September

Frost fighting equipment, such as water sprinklers, windmills and up to 40 helicopters, was used to counter potentially damaging frost in vineyards in parts of Hawke’s Bay during the night of 25/26 September. Some areas reported damage to 10–50 percent of chardonnay, pinot noir and merlot vines. Whakatu, near Hastings, recorded a grass minimum of –7.3°C, the lowest there in September since records began in 1983, with a screen minimum of –2.0°C, the second lowest September temperature on record there.

18 November

Late spring frosts created potential for damage to grapevines throughout Central Marlborough during the night of 17/18 November. An air minimum of –1.6°C was recorded at Blenheim Airport that night, the second lowest there in November since measurements began in 1941.

Extremely low minimum air temperatures in 2002 were measured at:

Location	Minimum temperature (°C)	Date of occurrence	Records began	Comments
June
Fairlie	–14.0	20	1925	Equal lowest
Tara Hills	–19.1	20	1950	Lowest
Ranfurly	–12.5	20	1975	Lowest
Twizel	–13.0	22	1972	Lowest
Lauder	–15.4	22	1982	Lowest
Balclutha, Finegand	–7.5	23	1965	Lowest
Haast	–5.1	26	1950	Lowest
September
Whakatu, Hastings	–2.0	26	1983	2nd lowest
October
Lumsden	–4.1	4	1987	Lowest
Taupo Airport	–5.1	5	1976	Lowest
Motu	–5.8	5	1991	Lowest
Waiouru Military Camp	–6.3	5	1966	Lowest
Culverden	–5.0	15	1983	Lowest
Arthurs Pass	–5.0	21	1978	Equal lowest
November
Blenheim Airport	–1.6	18	1941	2nd lowest

Snowfall

Between April and October there were at least seven periods with snowfall, three of which occurred to near sea-level in the South Island. The mid-Canterbury mid-August snowfall event was particularly severe.

2 April

Cold southerlies produced snowfall on Mt Taranaki, to its lowest level on record for the time of year. Snow also lay on the Desert Road, and in hill country areas on Banks Peninsula.

25–28 May

Bitterly cold south-westerlies brought snowfall to near sea level in Otago and Southland. On the 26th dozens of motorists were left stranded on SH1 north of Dunedin, which was closed for some hours due to snow and ice. Some inland Southland and West Otago roads were also closed because of snow, 30–40cm deep in places. Some schools closed. Power failures affected some areas. Snow lay a few centimetres deep in Dunedin, where day-time maximum temperatures reached only 3°C. Snow was still lying in the Mainiototo Valley on the 31st, where thousands of cattle and sheep where suffering from exhaustion due to the cold and lack of feed. Snow also lay on the North Island’s Desert Road on the 28th, but it remained open.

15–21 June

Snowfall occurred in high country areas of Canterbury and Otago on the 15th and again between the 17th and 21st. Heavy snow also occurred throughout mid-Canterbury and inland Otago over the 17th and 18th, being 10–40 cm deep in many areas. Christchurch airport was closed due to snowfall settling over that period and SH1 was closed due to snow from Dunsandel to Temuka for the first time in 26 years, leaving hundreds of travellers stranded. In and near Ashburton, powerlines failed due to the weight of snow, leaving more than 4000 homes without power. Hundreds of rural people were isolated in their houses. The Milford road and high-country pass roads were also affected. Snowfall lay 1 m deep on the 22nd and 23rd at Mt Cook Village.

15 July

Snowfall resulted in the closure of the North Island’s Desert Road, where 30 motorists had to be rescued by the army, as well as parts of SH47 through National Park and SH5 between Taupo and Napier (where 3 cm of snow lay). 14 cm of snow lay at Waiouru and 30 cm elsewhere.

18 August

Snowfall overnight resulted in the closure of the North Island’s Desert Road.

26 August

Snowfall also occurred in Queenstown-Southern Lakes district, Central Otago, parts of Southland, the hill country around Dunedin, and to low levels on the Port Hills in Canterbury. On the 27th ice closed the North Island’s Desert Road.

14 October

Cold southerlies brought snowfall to the Desert and Rimutaka Hill roads, as well as to South Island alpine passes.

Low soil moisture levels and record low monthly rainfall

January

Low rainfall since December 2001 had resulted in significant soil moisture deficits in parts of inland Southland. As a result soil moisture conditions were drier than usual in the south of the South Island.

February

Low rainfall persisted in inland Southland continuing significant soil moisture deficits in that region, with moderate deficits in Central Otago.

March

Significant soil moisture deficits in Otago spread to parts of inland south Canterbury. Moderate deficits existed in Gisborne, Wairarapa, central Marlborough and the Canterbury Plains.

April

Significant soil moisture deficits still existed in Central Otago and inland south Canterbury for the time of year.

September

Significant soil moisture deficits became apparent in central Marlborough and soil moisture levels were below normal in other parts of the eastern of the South Island, particularly in South Canterbury, and northern and Central Otago.

October

Soil moisture deficits persisted in central Marlborough, where rainfall was 50 percent or less of average. Significant soil moisture deficits developed in northern and Central Otago and inland South Canterbury.

November

Rainfall was below average for the fifth consecutive month in central Marlborough, and totals were 50 percent or less of normal in Northland and Bay of Plenty. Significant soil moisture deficits persisted (for the 3rd consecutive month) in central Marlborough, and continued in northern and Central Otago, and South Canterbury. Soil moisture was also well below average for the time of year in Northland, Bay of Plenty, Gisborne and Hawke’s Bay.

December

Much of Marlborough’s December rainfall occurred at the end of the first week of the month, providing welcome although only temporary relief from the previously very-dry soil conditions that had affected the region. However, significant soil moisture deficits resumed there from mid-month, and also spread throughout most of Otago and Canterbury. At the end of December soil moisture was well below average for the time of year in eastern Northland, coastal Bay of Plenty, Gisborne, Hawke’s Bay, Manawatu and parts of Wairarapa.

Some locations measured extraordinary low rainfall at various times during the year. These were:

Location	Rainfall (mm)	Percentage of normal	Year records began	Comments
March
Gisborne Airport	12	12	1905	3rd lowest
Chatham Islands	18	25	1951	Lowest
May
Napier Airport	9	14	1951	2nd lowest
Napier, Nelson Park	12	18	1870	2nd lowest
Kaikoura	9	10	1949	Lowest
Timaru Airport	6	12	1957	2nd lowest
Wanaka Airport	7	11	1992	Lowest
Lauder	8	29	1986	Lowest
July
Motueka, Riwaka	16	10	1943	Equal lowest
Nelson Airport	17	19	1941	3rd lowest
Appleby	16	17	1932	3rd lowest
Blenheim Airport	18	25	1941	3rd lowest
Winchmore	19	28	1947	3rd equal lowest
Lauder	1	5	1943	Equal lowest
Ettrick	6	15	1985	Lowest
September
Middlemarch	10	35	1931	2nd lowest

Floods and high rainfall

There were at least twelve high-rainfall/flood-producing events during 2002. These were more frequent in the North Island, but the northern half of the South Island also had its fair share. The most significant episodes are listed below.

3 January

Heavy rainfall (as much as 38 mm in an hour) deluged Westport with some flood damage reported. High rainfall (64 mm) also occurred in Balclutha on the same day.

10 January

Thunderstorms over Wellington City resulted in torrential rainfall (about 40 mm in 30 minutes, and 52 mm in an hour) and flash floods in the city center just after 7pm. This rainfall event had an average recurrence interval of well over 100 years. Thunderstorms, some with hail, and surface flooding also occurred over Wanganui, Manawatu, the central and eastern North Island, Buller and Nelson. Rainfall at Napier Airport totalled 29 mm in the hour to 9pm. Hastings rainfall totalled 77 mm for the 24 hours to 9am on the 11th.

12–13 January

Houses were flooded and evacuated in Akaroa, the Kowhai Bridge washed out, and the water supply to Akaroa cut after heavy rainfall over the 12th to 13th. The same weather system produced high rainfall, slips and surface flooding throughout Canterbury and the Kaikoura Coast (109 mm at Hanmer Forest, 106 mm at Kaikoura, 100 mm at Snowden for the 24 hours to 9am on the 13th). SH1 was closed due to flooding in several places, with the Orari Bridge washed out south of Oamaru. High rainfall and flooding also occurred near Thames in the North Island, where the Tararu Stream overflowed its banks, forcing 25 homes to be evacuated.

18 January

Further high rainfall (as much as 70 mm) occurred in parts of northern and inland Canterbury.

11–13 February

High rainfall totalling 89 mm was recorded at New Plymouth Airport on the 11th, with thunderstorms during the afternoon. Further high rainfall totalling 85 mm was recorded for the 24 hours to 9am on the 13th at Whakatu.

21 February

Whitianga, on the Coromandel, and Great Barrier Island were flooded by torrential rainfall. Whitianga Airport recorded 71.8 mm in the three hours to 9am. Rainfall on Great Barrier Island totalled a massive 233.5 mm in the six hours to 9am that morning.

1 March

A ferocious rainstorm produced 98 mm between 3.05 and 4.05pm in Egmont Village. This caused serious flooding and car accidents in North Taranaki. Inglewood recorded 59 mm between 3.15 and 4.15 pm on the same day.

1 June

High rainfall totalling 70-90 mm was recorded at sites in the Bay of Islands.

14 June

High rainfall, 56 mm in 6 hours, with flooding and a landslide occurred in Granity, Westland.

17–18 June

Flooding at least 1 m deep occurred near Melling Station, Lower Hutt, after a 12-hour period of heavy rainfall. Rainfall totalling 46 mm was measured in the 5 hours to 2am on the 18th at Wallaceville. Slips occurred in other areas in the Wellington region.

18–20 June – weather bomb

Flooding and slips, with rainfall totalling 160 to 210 mm occurred throughout Northland, north Auckland and Coromandel over 18–20 June, with many areas in the Thames-Coromandel recording rainfall totals over 100 mm on the 20th. Coromandel rainfall totalled 215.5 mm on the 20th, with 88.5 mm occurring in the 90 minutes to 11pm. Thames Airfield recorded rainfall totalling 45 mm in the hour to 12.30am 21 June. Near Dargaville, flooding at Tangiteroria and in the lower Kaihu River was considered almost as severe as during Cyclone Bola. High easterly winds lashed Auckland, lifting some roofs. Peak wind gust of 124 km/hr was recorded at Musick Point. A Civil Defence Emergency was declared in the northern Coromandel Peninsula, which was the worst affected area, with high winds damaging roofs, power cuts to thousands of homes, and severe floods isolating the region. The flooding was reported as a 150-year event, devastating many houses and leaving many without sewerage systems. The region was still cut off on 21 June. An elderly woman was swept away by flood-waters at Waiomu. Many residents were evacuated from Waikawau, Tapu, Tarau and Te Puru. A state of emergency was also declared in the town of Putararu, due to severe flooding affecting water supplies. More than 20,000 Waikato houses were without electricity.

28 June

High rainfall, totalling 132 mm in 15 hours, drenched Granity in Westland for the second time this month, with thunderstorms. Eight homes were temporarily evacuated due to landslides and flooding. There were three major landslips on the road between Westport and Greymouth.

5 & 8 July

Surface flooding closed SH30 between Te Kuiti and Mangakino on the 8th. Three houses near Te Awamutu were evacuated due to flooding a few days earlier on 5 July.

11 July

High rainfall totals, up to 100 mm, were recorded at sites in eastern Northland and Auckland on the 11th. Serious flooding occurred around Kaukapakapa north of Auckland. Farther south, the Waikato River overflowed at Mercer on 12 July flooding 50% of 20 nearby farms, already saturated by weeks of wet weather.

6 August

High rainfall totals, up to 75 mm, recorded at sites in Gisborne resulted in surface flooding. Much higher rainfall occurred in the hill country to the north, where roads were closed and schools finished early.

17–19 September

Heavy rainfall recorded at Milford Sound for the 48 hours to 9am on the 19th totalled 459 mm, of which 315 mm occurred in 24 hours.

Some locations experienced unusually high rainfall at various times during the year. These were:

Location	Rainfall (mm)	Percentage of normal for the month	Year records began	Comments
January
Hanmer Forest	222	295	1905	2nd equal highest
Kaikoura	234	446	1950	Highest
Rangiora	174	319	1918	3rd highest
Christchurch Airport	138	297	1944	2nd highest
Christchurch Gardens	143	314	1864	Highest
Darfield	180	279	1920	2nd equal highest
Winchmore	153	263	1947	Highest
Timaru Airport	130	239	1957	Highest
Twizel	128	256	1973	Highest
Oamaru Airport	120	303	1941	2nd highest
Chatham Islands	169	322	1951	Highest
February
New Plymouth Airport	235	247	1944	2nd highest
Palmerston North Airport	119	199	1944	2nd highest
June
Westport Airport	356	180	1944	3rd highest
Hokitika Airport	458	207	1964	2nd highest
Arthurs Pass	921	297	1917	Highest
Mt Cook	590	220	1928	3rd highest
Haast	433	214	1941	2nd highest
Milford Sound	848	207	1930	3rd highest
Ranfurly	74	304	1943	3rd highest
Wanaka Airport	112	192	1992	Highest
Milford Sound	848	207	1930	3rd highest
Queenstown	165	225	1872	4th highest
Lauder	67	216	1982	Highest
Queenstown	165	225	1872	4th highest
July
Hicks Bay	259	191	1991	Highest
September
Milford Sound	1139	206	1930	2nd highest
Queenstown	223	290	1871	2nd highest
October
Invercargill Airport	163	180	1939	2nd highest
November
Christchurch	124	252	1864	4th highest

Tornadoes, gales, high winds, and rough seas

4 January – tornado

A tornado passed over the Levin golf course just before 4pm, leaving a number of trees uprooted.

6 February

Huge 6–8-m swells were generated in Cook Strait by a severe southerly storm off the coast east of the North Island. These resulted in ferry cancellations and forced a southern coast road to be closed in Wellington. Three people had to be rescued from the sea. Heavy 5-m swells also affected Gisborne, where the Jody F Millenium, a log carrier, was grounded in rough conditions on a sand bar. Farther south, gales and 5-m swells generated by the storm resulted in the sinking of five small boats in Lyttelton Harbour.

13–14 February

Another depression resulted in gale force southerlies with huge 6–8-m swells in Cook Strait. These resulted in fast-ferry cancellations.

3–4 April

Huge seas, generated by strong south-easterlies, battered eastern coastlines of both islands. Powerful waves smashed through walls of beachfront batches in Hawke’s Bay between Haumoana and Te Awanga south of Napier. Wellington’s southern coast road was closed by debris. Most Cook Strait ferry sailings were cancelled, affecting more than 2000 travellers. A 12-km stretch of SH1 south of Kaikoura was badly damaged and closed for 12 hours.

29 April

Further high seas (with 5.5 to 9-m waves) occurred with gale force southerlies through Cook Strait, resulting in the 8am fast-ferry from Wellington having to turn back and cancellations of other fast-ferry sailings for the day. The Inter-island ferry took 6 hours to cross.

3 May

A maximum wind gust of 139 km/h from the southwest was recorded at Taiaroa Head during the morning.

27–28 May

Gale-force westerlies affected Taranaki (where a roof was blown off a house) on the 27th and high winds in Waipukurau contributed to power cuts there. High winds occurred through Cook Strait on the 28th, resulting in fast-ferry cancellations. Winds in Waikato (where there were thunderstorms) gusted to 100 km/h on the same day.

15 June – waterspout

Three houses on the Kapiti Coast lost their roofs in high winds associated with a waterspout that passed over them at 12.30am.

14 July

Gale force south-south-easterlies with high seas and gusts to 160 km/h occurred through Cook Strait, resulting in delays for over 1500 ferry passengers.

22 July

Storm force northeasterlies battered Cape Reinga with gusts to 183 km/h, the highest gust there for any month since records began in 1974.

18–19 August

Gale force southerlies occurred through Cook Strait with high (at least 4-m) seas, resulting in the cancellation of a number of fast-ferry services on the 18th and 19th. Conventional ferry services were also hampered. A rail wagon on the Aratere was tipped over by an extreme wave. Southerly winds gusted to 124 km/h at Brothers Island on the 19th.

26–27 August

Waves as high as 12 m were reported around Banks Peninsula. Southerly gales damaged boats in Lyttelton Harbour. Waves as high as 10 m occurred in Cook Strait on the 27th. On the 26th, mean wind speeds reached 100 km/h from the southwest Taiaroa Head and 98 km/h at Le Bons Bay.

22 September

Severe northwest gales buffeted parts of Canterbury, resulting in damage to a number of properties. Wind gusts to 117 km/h were recorded at Rangiora and 115 km/h at Darfield.

25, 27 & 29 October – tornadoes

A tornado occurred at Taitapu, near Lincoln, southeast of Christchurch on the 27th, damaging trees in the area, with another near Halswell on the same day. Tornado-like winds ripped roofing iron off a house, and toppled fences in Blockhouse Bay, Auckland on the 25th. Another tornado was sighted in Auckland on the 29th.

1 & 11 November

Gale force north-westerlies buffeted the lower North Island on the 1st, with a maximum gust of 130 km/h recorded at Kelburn, Wellington. Further high winds on the 11th resulted in a few lifted roofs in Wellington, Wairarapa, and Hawke’s Bay. Power cuts occurred in some areas of Hawke’s Bay as tree branches damaged power lines.

Electrical storms

Thunderstorms with lightning were a particular feature of the January climate. There was a thunderstorm somewhere in New Zealand on twenty-two days during the month, including all but two days of the first three weeks.

2 January – spectacular lightning

Hokitika Airport recorded 481 lightning flashes, and 937 flashes for the first 4 days of the month.

4 January – person struck by lightning

A tourist was struck by lightning twice while tramping on the Ben Lomond track near Queenstown about 3pm.

1–3 & 16–22 March – frequent thunderstorms

Thunderstorms were relatively frequent on the West Coast, occurring on 1–3, and 16–22 March. They also occurred in Southland on 1–3 March, Nelson on 19–21 March, and Wellington on 21 March.

1/2 November – spectacular lightning

A spectacular display of lightning occurred over Northland, Auckland, and Coromandel during the night, with almost 500 lighting flashes detected over Auckland, and about 300 over both Whangarei and Whitianga.

8 December – lightning

Significant thunderstorms, with frequent lightning, occurred over parts of Wellington for almost an hour just after midnight.

Severe or damaging hail storms

3 July – golf ball-size hailstones

A 30-minute hail-storm struck Massey, west Auckland from about 9.30am, with some hail stones as large as golf balls.

12 September – hailstorm

Heavy hail fell in central Takaka just before noon, with hailstones reported as “pea to moth-ball size”, lying 10 cm deep in places.

12 September – hailstorm closes Wellington Airport

A localised, but rather heavy hail-storm occurred over Wellington’s eastern suburbs (of Mirimar, Kilbirnie and Lyall Bay) at about 7a.m., resulting in the temporary closure of the airport due to icy conditions on the runway. Pea-size hail-stones lay a few centimetres deep in areas, some still present after two hours.

27 October – golf ball size hailstones

Thunderstorms with large hail occurred in Canterbury. Hailstones, some the size of golf balls, fell in the Hornby area, damaging numerous strawberry plants. Other damages reported were dented vehicles and broken windows. Significant surface flooding affected Hornby shops after the event.

17 November – damaging hail

Hailstorms struck apple orchards in Motueka, some resulting in severe damage to crops. A few orchards lost 70–100 percent of their potential crop. Estimates of the losses in terms of export crops stood at $20 million.

Sunshine extremes

Some locations incurred extremes of sunshine hours at various times during the year. October was exceptionally sunny compared to average, with many locations throughout New Zealand experiencing one of the sunniest October’s on record.

2002 monthly sunshine extremes were:

Location	Sunshine (hours)	Percentage of normal	Year records began	Comments
January
New Plymouth Airport	311	126	1973	Highest
March
Nelson Airport	261	129	1949	2nd highest
Christchurch Airport	227	135	1949	Equal highest
June
Auckland	63	58	1910	Lowest
Taumarunui	27	38	1947	Lowest
New Plymouth	84	72	1953	3rd lowest
July
Invercargill Airport	122	145	1932	3rd equal highest
October
Kaitaia	242	130	1951	Highest
Auckland	255	134	1909	Highest
Rotorua	269	145	1930	Highest
Taumarunui	208	141	1947	2nd highest
Kaitaia	242	130	1951	Highest
New Plymouth	254	134	1915	Highest
Paraparaumu Airport	257	143	1953	Highest
Wellington, Kelburn	260	133	1928	Highest
New Plymouth	254	134	1915	Highest
Nelson Airport	283	131	1948	2nd highest
Blenheim	282	125	1930	3rd highest
Christchurch	272	133	1930	Highest
Nelson Airport	283	131	1948	2nd highest

Record low solar radiation was recorded at:

Location	Solar radiation (MJ m2/day)	Percentage of average	Year records began	Comments
January
Kaikoura	18.3	78	1969	Lowest
Winchmore	17.0	76	1960	Lowest
Timaru Airport	15.8	72	1984	Lowest
Dunedin Airport	16.0	80	1970	Lowest
February
Winchmore	15.6	83	1960	2nd lowest
June
Rotorua Airport	5.1	74	1969	Lowest

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.