New Zealand’s climate for 2009 was characterised by frequent see-saws in temperature.
Heat waves occurred in January and the start of February; May was the coldest on record; October had its lowest temperatures since 1945; and August was the warmest August ever. In individual months (especially September and November), daily temperatures frequently broke long-standing records, with extremely cold temperatures often occurring within a week or so of record hot events. Overall, there were two months with above average temperatures and four with below average temperatures.
For the year as a whole, temperatures were near average (within 0.5°C of the long-term average) for most of the country, but were between 0.5 and 1.0°C cooler than average in parts of Auckland, Waikato, Manawatu, southern Hawkes Bay, Wairarapa, Wellington, Marlborough, inland Canterbury, and eastern Otago. The national average temperature for 2009 was 12.3°C, 0.2°C below the long-term normal. The years 2000-2009 were a warm decade overall, with a 10-year average temperature of 12.6°C, 0.1°C above the 1971-2000 normal.
Rainfall during the year was below normal (50 to 80 percent of normal) in parts of Auckland, central North Island, northern Hawkes Bay, southern Wairarapa, north Canterbury, inland south Canterbury, and central Otago. Other areas received near-normal rainfall.
Nelson was the sunniest centre in 2009, recording 2571 hours, followed by Tauranga with 2540 hours, then Blenheim with 2477 hours.
Of the main centres, Tauranga was the warmest and sunniest, Wellington was the wettest, and Christchurch was the driest.
The broad climate setting changed from La Niña at the start of the year, to moderate El Niño conditions by the spring of 2009.
Notable climate features of 2009 (in various parts of the country) included the record warmth of January, the heatwaves of early February, and the record cold and extreme wet of May. At the end of June, Gisborne declared a State of Emergency due to flooding. An unusually icy, snowy period prevailed throughout June and July, followed by the record warmth of August, which contributed to a severe avalanche season. Unseasonable snowfalls then characterised the coldest October in 64 years. An extremely windy and dry November and December followed, resulting in significant soil moisture deficits in Northland, Central North Island, Canterbury, and Otago.
Section 1: The year in review
Broadly speaking, the overall climate (with clear geographical exceptions) was as follows:
- January: Very dry and sunny. Record warm in eastern areas.
- February: Heat waves at start, then a cool change. Wet and cloudy.
- March: Extremely dry, very sunny, and cool.
- April: A month of contrasts.
- May: Coldest May on record. Very wet.
- June and July: Cold and snowy.
- August: Warmest August ever. Very dry in eastern areas.
- September: Very sunny, with extreme temperature swings.
- October: Coldest October since 1945. Unseasonable snow.
- November: Extremely dry and windy, with extreme temperature swings.
- December: Sunny and dry, particularly in the north and east
January: Very dry and sunny; record warmth in eastern areas
January rainfall was less than half of normal over much of the country, the exceptions being Gisborne and Southland (with well above normal rainfall) and Manawatu and northern Taranaki (receiving near normal rainfall). At the end of January, soil moisture levels were below normal for most North Island areas except Gisborne and northern Manawatu, as well in Tasman district, northern Westland, Canterbury and south Otago. It was a sunny month for most regions, except Southland and Otago. January temperatures were well above average along the South Island east coast from Kaikoura to Mosgiel, and several sites in Canterbury and Otago recorded their highest mean January maximum temperatures ever. It was also warmer than normal in the east of the North Island, western Bay of Plenty, inland Canterbury and Otago, and much of Southland.
February: Heat waves at start, then a cool change; wet and cloudy.
Temperatures flip-flopped from above average over the first 12 days of February (which included record high temperatures at numerous locations) to below average for the remainder of the month. Heatwave conditions were experienced over the country from 7 to 12 February when temperatures of 34°C or more occurred in many locations on each day. February was wet for most of country except in the southwest. It was also very cloudy, with most areas recording below normal sunshine totals.
March: Extremely dry, very sunny, and cool
Record low March rainfall was experienced in parts of Wairarapa, Marlborough, north Canterbury, north and central Otago. It was also very dry in other areas, except the western Bay of Plenty and eastern Otago. Record high March sunshine totals were observed in Northland, Auckland, King Country and the central South Island, and sunshine totals were also above normal elsewhere. It was a cool month, with below average temperatures over most of the country.
April: A month of contrasts
April was a month of contrasts. It was wet in the north and west, dry in the south and east; cool in the north and east, warm in the south and west. Exceptionally low rainfall for April (less than 20 percent of normal) occurred in southern Hawke’s Bay and Tararua District. This resulted in significant soil moisture deficits there. Other eastern areas of both islands, around Auckland, and along the south coast of the South Island received below normal April rainfall (between 20 and 60 percent of normal). In contrast, double normal April rainfall was recorded in Northland and parts of the West Coast and Southern Alps. April temperatures were below average over most of the central and eastern parts of the North Island, while parts of the West Coast, coastal Fiordland, Southland and south Otago were warmer than average by between 0.5 and 1.5 °C.
May: Coldest May on record; very wet
It was an extremely early start to winter. The lowest May temperatures ever recorded, and very wet conditions, were experienced in most regions of New Zealand.
June–July: Cold and snowy
June and July continued cold. Slow-moving winter anticyclones brought extremely frosty, yet sunny, conditions between 16 and 26 June. It was extremely wet in the east of the North Island in June, due to heavy rain on June 28-29th. A Civil Defence Emergency was established in the Gisborne District on 30 June, due to flooding and slips. There were three extreme snow/ice events in June, and seven in July.
August: Warmest ever; very dry in eastern areas
Nationally, it was the warmest August ever, since records began 155 years ago. All regions of New Zealand experienced record-high August mean temperatures, but extreme high daily maximum temperature records were also set in numerous locations on August 15-16, and August 28-30. The remarkable warmth of August, combined with heavy snowfall in previous months, resulted in a series of major avalanches in South Island alpine areas. It was very dry in eastern areas of both Islands, with rainfall totals less than half of August normal.
September: Very sunny, with extreme temperature swings
It was a very sunny start to spring, with sunshine totals between 110 and 140 percent of normal across the country. Although temperatures were close to normal for the month overall, extreme temperature swings were typical. It was record-breaking cold on September 5-6 in many locations, when a large anticyclone became slow-moving over the country; and record warm on September 14 in eastern areas of the South Island during an extremely strong northwesterly wind event. A deep, wintry low brought record-cold temperatures, high winds, and snow and ice to the South Island on the 24th.
October: Coldest October since 1945; unseasonable snow
Nationally, it was the coldest October in 64 years, with all-time record low October temperatures in many areas. Temperatures were more than 2.0°C below average throughout eastern and alpine areas of the South Island, as well as in the lower half of the North Island. Record low October temperatures were recorded on the 4th/5th in most North Island locations, and on the 9th at many South Island sites. The exceptionally heavy snow event on the 4th/5th in the Hawkes Bay and Central North Island was estimated to be the worst in October since 1967. Well above normal October rainfall was recorded in the east of the North Island, as well as in Wellington, Marlborough and parts of Canterbury. In comparison, it was very dry and extremely sunny on the West Coast of the South Island.
November: Extremely dry and windy with extreme temperature swings
November was extremely dry in the northeast of the North Island, and eastern South Island. Record low November rainfall was observed in Northland, parts of Auckland, Coromandel, Bay of Plenty, Taupo, Canterbury, Otago and inland Southland. By the end of November, significant soil moisture deficits were seen in the northeast of the North Island, especially Northland, as well the Kaikoura Coast, Canterbury and Otago. It was also an exceedingly windy month. Several extreme temperature swings were observed during the month, with record cold November temperatures reported in the first half of the month, and record hot conditions observed in the second half of November.
December: Very sunny in the north and east
December sunshine totals were well above normal in the north and east of the North Island and parts of North Canterbury. Well below normal rainfall was recorded in much of the Far North District for December. It was also drier-than-normal in Central North Island, Bay of Plenty, Gisborne, southern Hawkes Bay, Tararua District, Wairarapa, Northern South Island, Canterbury and Otago. Soil moisture levels on 31 December 2009 were well below normal in the Far North, Central North Island and Eastern Bay of Plenty. Temperatures were near average (between -0.5°C and 0.5°C from average) for most of the country.
NIWA Analyses of month-by-month records show:
- The highest annual average temperature for 2009 was 15.8°C at Whangarei, followed by Kaitaia and Kaikohe with an equal-second of 15.6°C.
- The highest recorded extreme temperature of the year (38.0°C) occurred in Culverden on 8 February. It was the highest February maximum temperature ever recorded at this location. The second highest temperature for the year was 37.8°C in Cheviot on 8 February and the third highest was 37.3°C in Wairoa (East Cape) recorded on 1 February.
- The lowest air temperature for the year was -11.7 ºC recorded at Middlemarch on 19 July, followed by -11.0°C at Lake Tekapo and -10.4°C at Tara Hills (both recorded on 14 July).
- The highest recorded wind gust for the year (as archived in the NIWA climate database) was 184 km/h at Southwest Cape, Stewart Island, on 4 November (a November record at this site), with equal-second 183 km/h gusts also recorded at Southwest Cape (8 February), Palmerston North (8 June), and White Island (20 June) during the year.
- Mount Cook received the top three highest 1-day rainfalls in 2009; being 341 mm on 27 April, 321 mm on 16 May and 295 mm on 26 April.
- The driest rainfall recording locations were Ranfurly in Central Otago with 263mm of rain for the year, followed by Clyde with 299 mm, and then Middlemarch with 365 mm.
- Of the regularly reporting gauges, Cropp River in the Hokitika River catchment recorded the highest rainfall with 10956 mm, followed by Doon (Fiordland) with 7266 mm and North Egmont with 7040 mm.
- Wellington was the wettest main centre with 1274 mm; in contrast Christchurch was the driest of the six main centres with 589 mm.
- Nelson was the sunniest centre in 2009, recording 2571 hours, followed by Tauranga (the sunniest of the main centres) with 2540 hours, then Blenheim with 2477 hours.
- Whakatane had instrument problems at the start of the year so an annual sunshine total could not be computed. However, their 8-month total from May to December (1614 hours) is only one hour less than the Nelson total over the same period so they will definitely be in the race for 2010.
Section 2: Prevailing climate patterns – Switch from La Niña to El Niño
Overall, mean sea level pressures were below average to the east of New Zealand in 2009, resulting in more frequent southerly winds than normal over the country. Warmer than normal sea temperatures prevailed around New Zealand from January to April, but enhanced southerly winds in May brought much colder than normal seas to our coasts, which generally prevailed for the remainder of the year.
The start of the year was dominated by a weakening La Niña event in the equatorial Pacific. During autumn and winter, the tropical Pacific climate was neutral (neither El Niño nor La Niña). A weak El Niño developed in the tropical Pacific in early spring, and had strengthened to moderate intensity by November.
Over New Zealand, monthly wind-flow patterns were highly variable throughout the year:
- January: Settled, with frequent anticyclones. Warm, dry, and sunny.
- February: Heatwaves at first, but ended cold and unsettled in the south.
- March: Settled. Dry, sunny and cool.
- April: Wet in the north and west, dry in the south and east. More northerly winds than normal.
- May: Stormy and record cold; frequent southerly winds and snowfalls.
- June: Cold and frosty; with wintertime highs and frequent southerly winds.
- July: Cold, with frequent southwest winds and snowfalls.
- August: Record warm, with much more frequent northerly winds than normal.
- September: Settled, with stronger than normal northerly winds.
- October: Extremely cold, frequent southeast winds and uncommonly late snowfalls.
- November: Extremely windy and dry, with frequent strong southwest winds.
- December: More frequent southwesterly winds than normal.
Section 3: Temperature – Slightly cooler than average year
The national average temperature in 2009 was 12.3°C, 0.2°C below the 1971–2000 normal. In 2009, there were two months with above average temperatures and four with below average temperatures. The warmest location was Whangarei, with a mean temperature for the year of 15.8°C (0.1 °C above normal).
The average temperature during the decade 2000-2009 was 12.6°C, 0.1°C above the 1971-2000 normal. This continues the series of relatively warm decades experienced in New Zealand since the 1970s. From the historical 7-station series, the 2000s were just 0.02°C warmer than the 1980s (previously the warmest decade on record for New Zealand). From a separate 11-station series, the 2000s were 0.08–0.20°C warmer than the 1980s.
In Kaitaia, Warkworth, Dannevirke, and Le Bons Bay, 2009 was the coolest year on record (based on averaging the mean daily temperature).
Kaikohe and Appleby recorded their highest average maximum temperature on record and Kaitaia, Pukekohe and Dannevirke recorded their lowest average maximum temperature on record (based on averaging the maximum temperature recorded each day).
Taumarunui, Dannevirke, Hanmer, Le Bons Bay and Queenstown recorded their lowest average minimum temperature on record (based on averaging the minimum temperature recorded each day).
Table 1: Near or record high or low annual average temperatures for 2009:
|Location||mean temperature(°c)||Departure (°C)||Year records began||Comments|
|Le Bons Bay||11.0||-0.3||1984||Lowest|
|Mean Maximum Temperature|
|Le Bons Bay||14.3||-0.2||1984||4th-lowest|
|Mean Minimum temperature|
|Le Bons Bay||7.8||-0.3||1984||Lowest|
New records for temperature extremes were set during the February 2009 heat wave, with extremely high day and night time temperatures especially in the east of the North Island.
Table 2: Near or record high or low annual temperature extremes for 2009:
|Location||Temperature(°C)||Date of occurrence||Year records began||Comments|
|Highest extreme maximums|
|Nugget Point||28.7||Jan-25th||1970||Equal 4th-highest|
|Highest extreme minimums|
|Lowest extreme maximums|
|Lowest extreme minimums|
Section 4: Sunshine – Above normal in many locations
It was a sunny year, with most locations in New Zealand recording near or above normal sunshine totals. Sunshine hours were above normal in Northland, central areas of the North Island, East Cape, southern Hawke’s Bay, West Coast, Canterbury and southeast Otago. Kaitaia, Tauranga, Taumarunui and Greymouth experienced their sunniest years on record. The sunniest centre in 2009 was Nelson, recording 2571 hours, followed by Tauranga (the sunniest of the main centres) with 2540 hours, then Blenheim with 2477 hours. The Whakatane site had instrument problems at the start of the year so an annual total could not be computed. However, their 8-month total from May to December (1614 hours) is only one hour less than the Nelson total over the same period so they will definitely be in the race for 2010.
Table 3: Near or record high sunshine hours for the year 2009:
|Location||Sunshine (hours)||Percent of normal||Records began||Comments|
Section 5: Rainfall – Below normal in many areas
Rainfall during the year was below normal (50 to 80 percent of normal) in parts of Auckland, central North Island, northern Hawkes Bay, southern Wairarapa, north Canterbury, inland south Canterbury and central Otago. Other areas received near-normal rainfall.
Table 4: Near or record low annual rainfall for the year 2009:
|Location||Rainfall (mm)||Percentage of normal||Year records began||Comments|
Of the regularly reporting gauges monitored by NIWA, Cropp River in the Hokitika River catchment recorded the highest rainfall with 10956 mm, followed by Doon (Fiordland) with 7266 mm for 2009. Ranfurly in Central Otago was the driest of the sites where NIWA records rainfall, with 263 mm of rain for the year (62 percent of normal), followed by Clyde with 299 mm (72 percent of normal), and then Middlemarch with 365 mm (70 percent of normal).
Near record values of annual 1-day rainfall extremes occurred at only two localities; Kaitaia and Tara Hills.
Table 5: One day rainfall extremes for 2009:
|Location||1-day extreme rainfall (mm)||Date||Year records began||Comments|
Section 6: 2009 climate in the six main centres
Tauranga was the warmest and sunniest of the six main centres (the Tauranga 2009 sunshine hours total was the highest ever at this location since records began in 1933). Wellington was the wettest of the main centres, and Christchurch was the driest.
Table 6: 2009 Climate in the six main centres
|Location||Mean temp. (°C)||Departure from normal(°C)||Rainfall(mm)||% of normal||Sunshine (hours)||% of normal|
|Aucklanda||14.6||-0.7||Below average||955||81%||Well below normal||2176||108%||Above normal|
|Taurangab||15.1||0.5||Above average||1221||101%||Near normal||2540||113%||Highest|
|Hamiltonc||13.2||-0.3||Below average||1088||90%||Below normal||2120g||106%||Above normal|
|Wellingtond||12.4||-0.4||Below average||1274||106%||Above normal||2079||101%||Near normal|
|Christchurche||11.1||-0.5||Below average||589||94%||Below normal||2170||103%||Near normal|
|Dunedinf||10.8||-0.3||Below average||736||91%||Below normal||1704||107%||Above normal|
aMangere b Tauranga Airport c Hamilton Airport d Kelburn e Christchurch Airport fMusselburgh g Ruakura
Section 7: Significant extremes
There were numerous heavy rainfall events during 2009, about fifteen of which produced significant flooding and property damage. The worst flooding events during 2009 were those of 27 April on the West Coast, 16-20 May in Canterbury, Otago, and alpine areas of the South Island, and 28-30 June in Gisborne and the Manawatu-Wanganui region (causing a State of Emergency to be declared in Gisborne).
On April 27, Mt Cook recorded 341 mm of rainfall (its highest April 1-day total since records began in 1928). Torrential rain also occurred in Greymouth on the 27th, and roads became impassable there. At least nine homes were evacuated on the eastern side of town. Flooding also forced the closure of SH6 at Punakaiki, and between Haast and Makarora. Trampers were stranded in the Mueller Hut in Aoraki Mt Cook National Park, and about 120 people were evacuated from the Milford Track by helicopter. On 17 May, SH1 south of Ashburton, was closed for several hours after the Rangitata River burst its banks. The main railway line between Rangitata River and Temuka was also closed by flooding. Inland, 33 people were evacuated in Omarama, as water was up to 1 m deep in places after a stopbank designed to cope with a 100-year flood was overtopped. A major slip closed SH8, on the Omarama side of the Lindis Pass. On 18 May, farmers near Balclutha used boats to rescue sheep stranded by the flooded Clutha River. The Skippers Road in Queenstown was closed until further notice, after slips and washouts. The previous three days of rain had also damaged many roads in the Queenstown Lakes area, with access requiring four-wheel drive vehicles. On 29 June, heavy rain caused slips and the closure of SH4 between Raetihi and Wanganui. SH57 between Palmerston North and Linton was flooded, and slips occurred in the Manawatu Gorge. On 30 June, the residents of the small settlement of Mangatuna just out of Gisborne were evacuated following heavy rainfall. Many slips affected the Napier-Taupo Road, and SH2 between Napier and Wairoa, although both remained open. A Civil Defence Emergency was established in the Gisborne District on the morning of the 30th.
It was a very snowy year, with an extended snow season that started in April and finished in October. Numerous snowfall events, and the record warmth of August, contributed to a high-risk avalanche season in late winter/early spring. Significant snowfalls, which were widespread and to low levels, were observed 31 May, 16 June, 2-5 July, and 4-6 October.
On 31 May, snow and slips closed the highway between Opotiki and Gisborne as wintry conditions brought snow and ice to the country's roads. Snow fell to sea level along Wellington's south coast and from Southland to Kaikoura, and blanketed high-country passes, including the Rimutaka Hill Road summit and Desert Road. Snow settled to about 200 m inland and elsewhere around Canterbury, with about 8 cm on the ground near Springfield and in parts of Otago. On 16 June, Dunedin Airport and many roads were closed, after snow fell to low levels in Otago and Southland. Flights were cancelled and some schools in Dunedin were closed for the day. Heavy snow on 2-3 July closed the Desert Road between Rangipo and Waiouru overnight, and also closed the Haast Pass. Cromwell was cut off, and schools in the area were closed. A series of avalanches on 1-2 August blocked the only road access to Milford Sound for 10 days, as both ends of the Homer Tunnel were buried in more than 100,000 tonnes of debris. The snow on October 4 – 6 in the Hawkes Bay and Central North Island was exceptionally late and very heavy, and estimated to be the worst in October since 1967. Hundreds of travellers were stranded as numerous roads were closed, and there were heavy lambing losses. Snowfall was also observed in Taranaki, Waikato and Rotorua on 6 October, for the first time in about 30 years around Rotorua.
It was a very windy year overall, particularly in May.
Gale force winds on 3 January caused havoc in Canterbury, with more than 10,000 homes left without power. Strong winds buffetted Wellington on 15 and 17 May, damaging power lines and cutting power, cancelling flights and causing property damage. On 23-24 May, southerly gales hammered Wellington, closing roads, tearing boats from their moorings, and damaging trees, roofs and power lines. Cook Strait ferries were cancelled, and flights were delayed, cancelled or diverted. On 23 July, Wellington and the Wairarapa were affected by high winds, which brought down trees onto high voltage lines, briefly cutting power to about 4,000 customers from Masterton to Castlepoint. Further north, powerlines between Tokomaru Bay and Ruatoria were also damaged by the strong northwesterlies. On September 14th, record-high wind gusts were experienced over the southern half of the South Island during a storm-force northwesterly event. Damage included felled power lines and lifted roofs on the Otago peninsula, and in Arrowtown, a tree felled by the wind crashed onto a vehicle, killing the driver. Gusty cross-winds on 4-5 October forced the closure of New Plymouth airport for 20 hours. The strong winds also brought down trees and cut the power supply to about 1,000 properties in Taranaki, and about 1,200 homes in the Rotorua District. High winds, together with heavy snow, brought down trees and power poles across the central North Island, leaving about 1,300 people without power. Some properties were without power for four days. On 13-15 November, strong winds caused havoc in Canterbury and Masterton, grounding helicopters and planes, felling trees, and downing power lines.
Soil moisture levels at the end of January were below normal for much of the North Island (except Gisborne and northern Manawatu), as well as in the Tasman District, northern Westland, north and south Canterbury, and south Otago. Rainfall in the latter part of February returned soil moisture levels to near normal status across much of the country. By April, significant soil moisture deficits (more than 50 mm below normal levels) had re-developed in southern Hawkes Bay and the Tararua District, but were short-lived due to wet conditions in these areas in May. After a windy and extremely dry November, significant soil moisture deficits (more than 50 mm below normal levels) had developed in Otago, Canterbury, the Kaikoura coast, Northland, and parts of Auckland, Coromandel, Bay of Plenty, central North Island, Gisborne and Hawkes Bay. However, rainfall in the first week of December returned soil moisture levels back to near normal in most regions, except Northland, central North Island, Bay of Plenty and Otago.
Climate summary for 2009 (PDF 241 KB)
For further information, please contact:
Dr James Renwick, NIWA Principal Scientist, Climate Variability & Change
Phone +64 4 386 0343
Mobile +64 21 178 5550
Dr Andrew Tait, Climate Scientist, NIWA National Climate Centre
Phone +64 4 386 0562
Mobile +64 27 327 7948
Acknowledgement of NIWA as the source is required.