Significant weather and climate events – 2008
National Institute of Water & Atmospheric Research
PART ONE: Temperature & High Rainfall
High temperatures
2008 was notable for two periods of significant heat waves, one in January and the other in March. Many new records of extreme monthly maximum temperatures were established in January, March and November.
- Heatwave conditions – 30 December – 22 January
The highest temperature during January 2008 was 34.8 ºC recorded at both Timaru Airport on the 12th and Waione on the 22nd.
From the 30th December to 22nd of January, apart from two days, heat wave conditions occurred in inland and eastern areas of the South Island. At least two locations record temperatures of 30°C or more over this period. Towards the end of this period numerous forest and scrub fires occurred. Wallaceville (Upper Hutt) recorded its highest January temperature on record of 30.9°C (records commenced in 1940) on the 21st and Palmerston North 31.8°C on the 22nd (records commenced in 1918).
Mean temperatures were at least 0.5 ºC above average in the east of the North Island, and from 1 to 2°C above average over the remainder of New Zealand, and over 2°C in some parts of central and north Otago. The national average temperature of 18.3°C was 1.3°C above average.
- 18-21 March heatwave
The highest temperature during March 2008 was 34.8 ºC recorded at both Timaru Airport, and 35°C (rounded to the nearest degree) at Culverden and Woodbury on the 19th. These temperatures were the highest for 2008 to date. The 35°C was 1°C less than the highest ever New Zealand March temperature of 36°C recorded at Ashburton in 1956. From the 18th to the 21st heatwave conditions occurred in inland and eastern South Island areas, with temperatures of 30°C or more, and many locations recording their highest March temperatures on record.
The National average temperature of 16.5°C was 0.8°C above average. Mean temperatures were 1°C above average in the Waikato, western Bay of Plenty, Taranaki to Manawatu and parts of the west of the South Island, and at least 0.5°C above average in much of the remainder of the North Island, Marlborough, Westland, and parts of Canterbury and Otago.
- Warm June
The national average temperature of 8.9°C was 0.5°C above average. Mean temperatures were particularly high in inland South Canterbury and Otago, being 1.5 to 2 °C above average. Western and northern North Island areas were also warmer than normal for June (by between 0.5 to 1°C). The highest temperature during June 2008 was 23.1°C recorded at Waipara West on the 15th. This was only 0.9°C below the record South Island temperature for June of 24.0°C recorded at Kaikoura and Temuka on 2 June 1976. Westport Airport, Haast, Appleby, Blenheim Research Centre and Tekapo recorded their highest ever June maximum air temperatures.
- 11 and 19 July
The highest temperature during July 2008 was 22.0ºC recorded at Kaikoura on the 11th, the second equal highest July temperature on record (since 1964) at this location. The North Shore recorded 20.2°C on the 19th, which was the third highest July temperature at this location.
- August
The highest temperature during August 2008 was 19.9°C recorded at Haast on the 26th during a strong easterly air flow. The minimum temperature of 12.9°C at Haast on the 25th was also the highest for the country for August. Both of these temperatures were the highest August temperatures (maximum and minimum) at this location since records began in 1949.
- November warm spells
The highest temperature during November 2008 was 33.3°C recorded at Waione (Wairarapa) on the 24th (not a November record for this location). The minimum temperature of 19.2°C at Wanganui on the night of the 23rd/24th was the highest minimum for the country for November. Warm northwesterlies also brought record high temperatures in Otago and Canterbury on the 14th and 15th.
PART TWO: Low Rainfall, Snow, Sunshine, Tornadoes, High Winds, Hail, Electrical Storms, Fog
Low soil moisture levels and record low monthly rainfall
During the first part of the year from January to March drought and extremely low rainfall occurred in the west of the North Island, Marlborough and Wairarapa. Dry conditions were affecting all eastern areas by the end of summer.
- January
By the end of January severe soil moisture deficits (more than 130 mm) had developed from Auckland to the King Country, South Taranaki, northern Manawatu, Hawke’s Bay to Wairarapa, Wellington, and persisted in the South Island from Marlborough to central Canterbury. The remainder of the North Island, except Northland and Horowhenua were recording significant soil moisture deficit, as well as other northern and eastern South Island areas from Nelson through to inland Southland. The combination of the hot and dry conditions meant that dairy farmers in some areas started drying off dairy stock, with sheep farmers selling stock early. Water restrictions were imposed in Wanganui, South Taranaki and parts of the Waikato, with drought committees being formed in Southland and Canterbury.
- February
By the last day of February severe soil moisture deficits (more than 130 mm) had persisted in the Hauraki plains, parts of the Waikato, southern Taranaki and northern Manawatu, in the east from Napier to the Wairarapa, central Marlborough, and in parts of Otago and Southland. Much of the remainder of the North Island, except Northland, were recording significant soil moisture deficit, as were Nelson, and much of Otago and Southland.
- March
By 29th March severe soil moisture deficits (more than 130 mm) were present in parts of Auckland, Waikato, South Taranaki, Manawatu, Wairarapa and Marlborough. Significant soil moisture deficits (more than 110 mm) persisted throughout much of the west of the North Island, and from the Heretaunga Plains to Wairarapa, and in the east of the South Island. The combination of the hot and dry conditions meant that dairy farmers continued drying off dairy stock, with sheep farmers selling stock early. The stock feed situation remained very low in the drought areas.
- April
April rainfall ended the severe and significant soil moisture deficits in much of the North Island. Significant soil moisture deficits (more than 110 mm) persisted in Canterbury, north and central Otago.
- November
Significant and severe soil moisture deficits had developed throughout eastern areas from Gisborne to Otago by the end of November.
- December
Soil moisture levels were low in eastern North Island areas, Waikato and in much of Southland, being between 10 and 50 mm lower than normal for this time of the year as at the end of December.