Rainfall: Dry in many northern and central North Island areas, and western and inland areas of the South Island. Wetter in Bay of Plenty, Nelson, and Southland
Temperatures: Cold in many parts of the North Island, and parts of the South Island
Soil moisture: Significant deficits persist in North and Central Otago
Sunny in the northeast of the North Island, southern parts of the South Island
April climate continued the generally cold dry theme of March. Rainfall was well below average over much of the northern half of the North Island until almost the end of the month. Less than 50 percent (half) of average April totals occurred in Northland, Auckland, much of Waikato, the central North Island Plateau, Westland, Fiordland, south Canterbury, and the Southern Lakes district. In contrast, rainfall was well above average in parts of Bay of Plenty and Southland. Soil moisture levels were below average in the north and east of the North Island, with some significant deficits in North and Central Otago. Mean temperatures were well below normal throughout much of New Zealand, being 2.0°C below normal in the King Country, and the Wairarapa. It was sunny in parts of the north, and the southern half of the South Island.
The generally cooler, drier April climate pattern was due to more frequent anticyclones (“highs”) in the south Tasman Sea extending across the South Island to the Chathams, with above average pressures over New Zealand. This pattern produced more frequent easterlies to the north of the North Island. The period from the 13–26th was dominated by generally very settled anticyclonic conditions.
Highlights
- The highest April 2004 temperature was 28.9°C, recorded at Darfield on the 2nd. This was their highest April temperature in measurements that commenced in 1939. Kaikoura recorded 27.5°C on the same day, the 3rd highest April temperature in measurements that commenced in 1964.
- The lowest temperature for the month was –8.0°C, recorded at Fairlie on the 9th, the 2nd lowest for April since observations started in 1925.
- A cold southerly outbreak produced snowfall in Canterbury near the foothills on the 6th. Snowfall occurred to about 500 m in the North Island on the same day, and hail was widespread throughout Wanganui; a storm produced a thick layer of hailstones (up to 20 cm deep in places) in the city, damaging roofs, and causing disruptions to traffic.
- Of the four main centres Auckland was the driest and Wellington was the sunniest. Rainfall and temperatures were below average in all four centres. Sunshine hours were above normal in Auckland, Wellington, and Christchurch, and near normal in Dunedin. For Auckland March was one of the driest and coldest on record.
- High intensity rainfall totalling 124 mm occurred in Motueka on the 8th. Further high rainfall totalling 207 mm occurred at Tauranga Airport over the 27–28th (130 mm on the 28th) with flooding, and totals exceeding 100 mm in other parts of Bay of Plenty. Stanmore Bay (Whangaparaoa Peninsula) had a violent electrical storm on the 29th.
- Wellington was the sunniest and Auckland the driest main centre. Rainfall was well below average in Auckland. Temperatures were below average in all four centres. Sunshine hours were well above normal in Dunedin, near normal in Auckland and Wellington, and below average in Christchurch.
Rainfall
Rainfall was less than 50 percent (half) of average April totals in Northland, Auckland, much of Waikato, the central North Island Plateau, Westland, Fiordland, south Canterbury, and the Southern Lakes district. Totals were well above average in parts of Bay of Plenty and Southland.
Temperature
The April national average temperature of 12.1°C was 1.3°C below normal, equal lowest since April 1993. Mean temperatures were up to 2.0°C below normal in the King Country and the Wairarapa.
Sunshine
Sunshine totals were above normal in Bay of Plenty, Gisborne, the MacKenzie Basin, much of Otago, and south Westland.
Full report
Full details of April 2004 summary.
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.