Friday 6 September 2002
Unusually mild in the North Island and northern South Island Above average rainfall in the central and eastern North Island and the south and west of the South Island Below average rainfall in the northeast of the South Island Less sunshine in many western and central North Island areas
The winter of 2002 was the 5th consecutive warmer than normal winter for New Zealand, in spite of the icy southerlies and snow blasts that occurred to sea level in Canterbury in June and reached the Volcanic Plateau and regions of the South Island in August. The national average temperature of 9.0°;C was 0.8°;C above normal, and 6th equal warmest for winter since reliable measurements began in the 1850s, due to rather mild conditions over the North Island. Only 2000 (9.1°;C), 1998 (9.1°;C), 1989 (9.1°;C), 1984 (9.4°;C) and 1971 (9.2°;C) were warmer. This was unusual, since cool south westerlies were more frequent than normal for the time of year. Higher than normal sea temperatures around the country contributed to the warmer winter.
Mean temperatures were at least 1.0°;C above normal throughout most of the North Island and northern South Island (due to well above average overnight minima). Mean temperatures were about 0.5°;C above average over much of the South Island.
Rainfall was above average in central and eastern North Island regions, as well as the south and west of the South Island. It was drier than average in the northeast of the South Island. Sunshine was below average in many western and central North Island areas. Only Dunedin was sunnier than average. Winter overall was windier than normal.
Other features of the winter were extremes of high and low daily temperature, at least three significant snowfall events, five high wind and seven heavy rainfall/flooding events.
The winter climate pattern was dominated by more depressions (‘lows’) than usual east of the South Island. These resulted in more frequent southwesterly winds over New Zealand.
Above average rainfall in the central and eastern North Island and the lower and west of the South Island Below average rainfall in the northeast of the South Island
Rainfall was 115 to 150 percent (one and a half times) of normal throughout much of Wanganui, Manawatu, King Country, Tongariro, Taupo, Gisborne, Hawke’s Bay, Westland, Fiordland, Southern Lakes and Central Otago, as well as parts of eastern Northland. However, rainfall was less than 75 percent (three quarters) of normal in much of Nelson, Marlborough, Canterbury, and parts of Bay of Plenty.
Unusually mild in the North Island and northern South Island
Mean temperatures were at least 1.0°;C above normal throughout much of the North Island, Marlborough and Nelson. However, they were more than 1.5°;C above normal in Waikato, Taranaki, Wanganui, Manawatu, the volcanic plateau, Gisborne and Hawke’s Bay. Mean temperatures were about 0.5°;C above average over much of the South Island.
Near or record high mean winter temperatures were recorded at:
| Location | Mean temperature | Departure (°C) | Records began | Comments |
|---|---|---|---|---|
| Whangarei Airport | 12.8 | +1.1 | 1968 | 3rd highest |
| Warkworth | 11.7 | +0.9 | 1972 | 3rd equal highest |
| Auckland, Owairaka | 12.2 | +1.2 | 1949 | 3rd highest |
| Auckland Airport | 12.2 | +1.1 | 1962 | 3rd highest |
| Paeroa | 11.3 | +1.4 | 1947 | 2nd equal highest |
| Tauranga Airport | 11.4 | +1.3 | 1913 | 3rd highest |
| Whakatane Airport | 10.3 | +1.3 | 1975 | 3rd highest |
| Taupo Airport | 8.2 | +1.3 | 1976 | Highest |
| Hamilton, Ruakura | 11.2 | +1.9 | 1907 | Highest |
| Hamilton Airport | 10.4 | +1.4 | 1971 | 2nd highest |
| New Plymouth Airport | 11.2 | +1.4 | 1944 | Highest |
| Normanby | 10.5 | +1.4 | 1977 | Highest |
| Wanganui | 11.2 | +1.5 | 1937 | Highest |
| Turangi | 8.4 | +1.4 | 1968 | Highest |
| Chateau, Mt. Ruapehu | 4.2 | +0.8 | 1930 | Equal highest |
| East Taratahi | 9.0 | +1.4 | 1972 | Equal highest |
| Gisborne Airport | 11.3 | +1.5 | 1905 | Highest |
| Napier Airport | 10.7 | +1.5 | 1974 | Highest |
| Napier, Nelson Park | 11.2 | +1.7 | 1870 | Equal highest |
| Palmerston North Airport | 10.0 | +1.5 | 1962 | Highest |
| Levin | 10.1 | +1.0 | 1895 | 2nd equal highest |
| Paraparaumu Airport | 10.3 | +1.3 | 1953 | Highest |
| Wallaceville | 9.5 | +1.5 | 1940 | Highest |
| Wellington Airport | 11.0 | +1.3 | 1962 | Equal highest |
| Farewell Spit | 11.3 | +1.9 | 1971 | Equal highest |
| Nelson Airport | 9.2 | +1.9 | 1943 | Highest |
| Blenheim Research | 9.4 | +1.5 | 1932 | Highest |
| Blenheim Airport | 8.5 | +1.0 | 1941 | 2nd equal highest |
Less sunshine in many western and central North Island areas
Sunshine and solar radiation totals were below average in many western and central North Island areas, especially between Wanganui and the King Country, but near average in most other regions. Only Dunedin was sunnier than average.
Highlights
Extreme temperatures
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Very high August temperatures occurred on the 12th, as warm northwesterlies fanned the east coast of the South Island. This pushed temperatures up to an unofficial 24.8°C at Waipara in North Canterbury, almost a New Zealand record for the month of August. Other high temperatures that day were:
Location Maximum temperature (°C) Comments Darfield 23.3 Highest for August. Records began in 1939. Woodbury 23.0 Highest for August. Records began in 1993. Christchurch Gardens 22.8 2nd highest for August, 23.2°C in 1970. Records began in 1864. The lowest air temperature for the winter was –19.1°;C, recorded at Tara Hills, Omarama on the 20th of June.
High rainfall and flooding
- 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 2 am 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, many areas in the Thames-Coromandel recording rainfall totals over 100 mm on the 20th. Coromandel rainfall totalled 215.5 mm on the 20th, 88.5 mm occurring in the 90 minutes to 11pm. Thames Airfield recorded rainfall totalling 45 mm in the hour to 12.30 am 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 affect 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, 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 the 5th.
- 11-12 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. Further south, the Waikato River overflowed at Mercer on the 12th flooding 50% of 20 nearby farms, already saturated by weeks of wet weather.
- 6 August High rainfall totals, up to 75 mm, were recorded at sites in Gisborne, resulting in surface flooding. Much higher rainfall occurred in the hill country to the north, where roads were closed and schools finished early.
Snowfall and hail
- 17-18 June Snowfall occurred in high country areas of Canterbury and Otago on 15 June and again between 17 and 21 June. However, heavy snow occurred throughout mid-Canterbury and inland Otago over 17-18 June, 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 also affected, 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.
- 3 July A 30-minute hail-storm struck Massey, west Auckland from about 9.30 am, with some hail stones as large as golf balls.
- 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 3cm of snow lay). 14 cm of snow lay at Waiouru and 30 cm deep elsewhere.
- 18 August Snowfall overnight on the 18th resulted in the closure of the North Island’s Desert Road.
- 26 August Snowfall occurred in the Queenstown-Southern Lakes district, Central Otago, parts of Southland, the hill country around Dunedin, and to low levels on the Port Hills in Canterbury. The North Island’s Desert Road was closed due to ice on the 27th.
High winds
- 15 June Three houses on the Kapiti Coast lost their roofs in high winds associated with a waterspout that passed over their street at 12.30 am.
- 14 July Gale force south-southeasterlies with high seas and gusts to 160 km/h occurred through Cook Strait resulting in delays for over 1500 ferry passengers.
- 18-19 July Gale force southerlies and high (at least 4 metre) seas occurred in Cook Strait, 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.
- 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.
- 26-27 August Waves as high as 12 metres were recorded around Banks Peninsula. Southerly gales damaged boats in Lyttelton Harbour. Waves as high as 10 metres 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.
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.