Thursday, 6 March 2003
Sunny with significant soil-moisture deficits in many regions Average or below average rainfall in most regions Above average rainfall in some northeastern parts of the North Island Coolest summer overall since 1996/97
Summer commenced with a windier than normal December, followed by generally sunny, but cooler and much drier than average conditions during January and February. Significant soil-moisture deficits occurred throughout the summer in much of the eastern South Island, spreading to much of the North Island from January onwards. Extreme fire risk also developed in many areas.
Sunshine hours were above average in most regions, especially from Marlborough to Otago, with Christchurch recording its sunniest summer in over 50 years. Sunshine was near average in Northland, Auckland, and Waikato. Rainfall was about 50 percent (half) of normal in parts of central Hawke’s Bay, and Horowhenua. It was also drier than average in Taranaki, eastern Bay of Plenty, Taupo, Kapiti, Nelson, and in many eastern south Island areas from Kaikoura to Central Otago. In contrast, rainfall was above normal in parts of Thames, Coromandel, Gisborne, and eastern Northland, mainly due to significant heavy rainfall and, in some areas, flood-producing events at the start of January and at the end of February.
Temperatures were average or below average. For the season overall the national average temperature of 16.2°C was 0.4°C below normal, the lowest for summer since 1996/97.
Other features of the summer were unseasonable snow at the Homer Tunnel on Boxing Day, and unseasonable early frosts, extreme in some areas for February, occurring in inland and eastern regions between 20 and 23 February.
The Pacific El Niño event, although weakening, had some effect on the New Zealand summer climate pattern. Anticyclones (‘highs’) were more frequent than average in the Tasman Sea and well east of the Chatham Islands, keeping pressures a little higher than average over New Zealand. More frequent westerly winds occurred south of the country in the Southern Oceans.
Sunny in most regions
Sunshine and solar radiation totals were near average in Northland, Auckland, and Waikato, but at least 110 percent of average in most other regions. It was very sunny in the east, especially from Marlborough to Otago. Well above average summer sunshine hours were recorded at:
| Location | Summer sunshine (hours) | Percentage of average | Year records began | Comments |
|---|---|---|---|---|
| Christchurch Airport | 801 | 126 | 1949 | Highest |
| Dunedin, Musselburgh | 604 | 121 | 1948 | Well above average |
Record high summer solar radiation was recorded at:
| Location | Summer solar radiation (MJ m–2 / day) | Percentage of average | Year records began | Comments |
|---|---|---|---|---|
| Blenheim Airport | 24.7 | 113 | 1992 | Highest |
Average or below average rainfall in most regions
Rainfall was about 50 percent (half) of normal in parts of central Hawke’s Bay, and Horowhenua. It was also drier than average in Taranaki, eastern Bay of Plenty, Taupo, Kapiti, Nelson, and in many eastern South Island areas from Kaikoura to Central Otago, with rainfall less than 75 percent (three quarters) of normal. Well below average summer rainfall was recorded at:
| Location | Summer rainfall (mm) | Percentage of normal |
|---|---|---|
| Napier Airport | 88 | 48 |
| Levin | 113 | 45 |
Above average rainfall in some northeastern parts of the North Island
Rainfall was at least 125 percent (one and a quarter) of normal in parts of eastern Northland, Thames, Coromandel, and Gisborne. Near record high summer rainfall was recorded at:
| Location | Summer rainfall (mm) | Percentage of normal | Year records began | Comments |
|---|---|---|---|---|
| Whitianga Airport | 507 | 162 | 1991 | 2nd highest |
| Paeroa | 622 | 228 | 1914 | Highest |
| Hicks Bay | 410 | 166 | 1991 | Well above average |
Near or below average temperatures everywhere
Mean temperatures ranged from average to 0.4°C below average in most regions, and were 0.5 to 0.9°C below average throughout much of Northland, Auckland, King Country, north Westland, and Central Otago.
Highlights
Extreme temperatures
- The highest air temperature for the season was 36.5°C, recorded at Darfield on 31 December; the highest December air temperature on record there since records began in 1939.
- The lowest air temperature for the summer was –3.0°C, recorded at The Chateau, Mt Ruapehu on 15 January.
High rainfall
- High rainfall, totalling 100 to 200 mm was recorded throughout eastern Northland, Coromandel, Waikato, and Bay of Plenty between 4 and 10 January. The wettest days were the 8th and 9th, when many locations recorded between 60 and 120 mm. The rainfall was also accompanied by wind and resulted in surface flooding in these regions, especially on the Coromandel, creating washouts in holiday parks, disrupting the plans of many campers.
- Further high rainfall occurred in eastern Northland, Coromandel, and Gisborne toward the end of February, and some houses in Paeroa were evacuated due to flooding on the 27th. Some rainfall totals were:
Location Rainfall total (mm) Date of occurrence Whangarei Airport 65.6 25 Feb Whitianga Airport 123.4 25–26 Feb Paeroa 279.8 26–27 Feb Hicks Bay 191.0 26–27 Feb
Persistent fog
- Wellington Airport was closed due to fog at times from 2 through 4 December as warm humid easterly airflow was cooled over cold water through Cook Strait, resulting in aircraft delays for thousands of passengers.
Unseasonable snowfall
- Snow lay at the Homer Tunnel on Boxing Day, with skiing still possible then at Whakapapa in the North Island.
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.