Thursday, 6 January 2003
Below average rainfall persists in eastern Northland and Bay of Plenty, dry in Canterbury and eastern Otago Significant soil moisture deficits in eastern Marlborough, Canterbury and most of Otago Above average rainfall in parts of Taranaki and Marlborough, and the southwest of the South Island Sunny in the east of the South Island and Hawke’s Bay
For much of the country, December was a sunnier, drier than average month in many eastern regions and cloudier and wetter than usual in some western districts.
Rainfall was above average for the first time in six months in central Marlborough, but continued below average in eastern Northland and coastal Bay of Plenty. Rainfall was 50 percent (half) or less of normal in coastal Bay of Plenty, the Heretaunga Plains of Hawke’s Bay, north Canterbury, coastal south Canterbury, and the north and east of Otago. Other regions with below average rainfall were eastern Northland, north Auckland, Coromandel, coastal Wairarapa, north Westland, the Kaikoura coast, mid Canterbury, Central Otago, and inland Southland.
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 have spread throughout most of Otago and Canterbury. Soil moisture is well below average for the time of year in eastern Northland, coastal Bay of Plenty, Gisborne, Hawke’s Bay, Manawatu and parts of Wairarapa.
December temperatures were near average in most regions. However, they were above average in Hawke’s Bay and Wairarapa, and below average in the southwest of the South Island. The national average temperature of 15.6°C was 0.1°C below the 1961–1990 normal.
Sunshine hours were above average in many eastern regions from Hawke’s Bay to Southland, but below average in the western North Island from Auckland to King Country.
December’s climate pattern was dominated by disturbed westerlies and south-westerlies over New Zealand, with anticyclones over the north and south-westerlies in the Tasman Sea, with below average pressures over the Southern Ocean.
Below average rainfall in many eastern regions
Rainfall continued below average in Bay of Plenty, December totals being 50 percent or less of normal in coastal areas. Rainfall was also 50 percent or less of normal in central Hawke’s Bay, north Canterbury, coastal south Canterbury, and the north and east of Otago. Totals were 75 percent or less of average in eastern Northland, north Auckland, Coromandel, coastal Wairarapa, north Westland, the Kaikoura coast, mid Canterbury, Central Otago, and inland Southland.
Near or record low December rainfall was recorded at:
| Location | December rainfall (mm) | Percentage of normal | Year records began | Comments |
|---|---|---|---|---|
| Warkworth | 35 | 30 | 1972 | 3rd lowest |
| Rangiora | 17 | 30 | 1965 | 2nd lowest |
| Middlemarch | 23 | 39 | 1916 | 3rd equal lowest |
| Dunedin, Musselburgh | 24 | 32 | 1918 | 2nd lowest |
| Ettrick | 30 | 53 | 1985 | Lowest |
| Gore | 50 | 54 | 1971 | 2nd equal lowest |
Above average rainfall in the northern South Island and many western regions
Rainfall totals were at least 125 percent of average in Marlborough, Nelson, and the Gisborne high country, and many western regions including the Waikato coast, north Taranaki, Wanganui, Wellington, parts of Buller, south Westland, Fiordland, the Southern Lakes, and the Southland coast.
Near average temperatures for most
Mean temperatures were at least 0.50°C above normal in parts of Hawke’s Bay and Wairarapa, and at least 0.5°C below normal in south Westland, Fiordland, and Southland. They were generally near average elsewhere.
Near record low mean daily maximum December temperatures were recorded at:
| Location | Mean daily maximum temperature | Departure (°C) | Records began | Comments |
|---|---|---|---|---|
| Taumarunui | 20.6 | –2.4 | 1947 | 3rd equal lowest |
| Tiwai Point | 15.7 | –1.5 | 1970 | Well below average |
Sunny in the east
Sunshine and solar radiation totals were 110 percent or more of average in many eastern regions from Hawke’s Bay to Southland, including Wellington. Sunshine hours were less than 90 percent of average in the west of the North Island from Auckland to King Country. Totals were near average elsewhere. Near record high December sunshine was recorded at:
| Location | December sunshine (hours) | Percentage of normal | Year records began | Comments |
|---|---|---|---|---|
| Christchurch Airport | 275 | 125 | 1949 | 3rd highest |
Highlights
Extreme temperatures
- The lowest air temperature for the month was –2.0°C, recorded at Fairlie on 27 December. This was the lowest December air temperature on record there since measurements began in 1928.
- The highest air temperature for the month was 36.5°C, recorded at Darfield on 31 December, the highest December air temperature on record there since records began in 1939.
Persistent Fog
- Wellington Airport was closed due to fog at times from the 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.
Funnel clouds
- Funnel clouds, although not reaching the ground like tornadoes, were sighted in Rotorua about 8.30pm on 2 December, and in Masterton about 6pm on the 4th.
Thunderstorms
- Significant thunderstorms, with frequent lightning, occurred over parts of Wellington for almost an hour just after midnight on 8 December.
Unseasonable snowfall
- Snow lay at the Homer Tunnel on 26 December, 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.