April 2005

Rainfall: Below average over much of New Zealand, especially Northland, Auckland, Coromandel, Bay of Plenty, Nelson and central Marlborough, with significant soil moisture deficits still present

Sunshine: Above average in most regions, with records in Northland, Auckland, Nelson and Dunedin

Temperature: Cooler in the lower North lsland and much of the South Island

April 2005 was exceptionally dry and very sunny month overall, with less than 25 percent of normal rainfall and near or record low rainfall totals in parts of Northland, Auckland, Coromandel, Bay of Plenty, Nelson and central Marlborough. Many locations in these regions recorded rainfall totals of less than 10 mm for the whole month. There was only 1 day in April with rainfall totalling at least 1.0 mm in both Whangarei and Nelson. Above normal rainfall occurred only in a few coastal areas of Hawke’s Bay and Wairarapa, and Central Otago. Severe soil moisture deficits occurred in Northland, with significant deficits in Auckland, Horowhenua, the Kapiti coast, Marlborough, and parts of Canterbury. Much of Northland has had only 20 to 30 mm of rainfall since the end of February. April’s sunshine hours were well above average for most, with new April record totals in Northland, Auckland, Nelson and Dunedin. While it was warmer than normal in parts of Northland, mean temperatures were below average south of Waikato and Gisborne, and in much of the South Island. The cooler conditions were due to frequent clear nights, along with cold southerly outbreaks toward the end of April. The national average temperature for April was 12.5°C (0.7°C below normal). With the passage of active fronts on 23rd and 24th, a vigorous cold southerly air-mass brought wintry conditions to the south and east, and snow settled on the North Island’s Desert Road, the Rimutaka Hill Road, and as low as 400 metres in the South Island. During April, anticyclones ('highs') were often centred west of New Zealand during April, with more frequent southerlies over the North Island. Apart from ANZAC weekend, depressions occurred well away to the south or east of the country.

Highlights

  • The highest temperature during April 2005 was 27.3°C recorded at Henderson (Auckland) on the 8th. The lowest temperature for the month was -5.8°C, recorded at Motu on the 29th.
  • A series of waterspouts were sighted off the Whangamata coast on the 1st. A small tornado was sighted in Greymouth on the 4th.
  • Fog and low cloud closed Wellington Airport from late afternoon to the evening on the 12th.
  • Major thunderstorms affected southern and eastern regions during the night of 23/24 and evening of 24 April, with lightning, wind squalls, and large hail stones, followed by wintry conditions.
  • Of the four main centres Auckland was easily the warmest, sunniest and driest. Rainfall was below average in all four main centres. Temperatures were near average in Auckland and below average in Wellington, Christchurch and Dunedin. Sunshine hours were well above average in Auckland and Dunedin, and below average in the other main centres.

Rainfall

Rainfall was well below average (less than 25 percent of normal) throughout much of Northland, parts of Auckland, Coromandel, Bay of Plenty, Nelson and central Marlborough. Totals were less than 50 percent of normal in Waikato, Taranaki, Marlborough, Buller, Westland and Fiordland, and also below normal in the west of the North Island from Wanganui to Wellington as well as Ruapehu, Tongariro and coastal areas of both Southland and Otago. Rainfall was at least 125 percent of normal in scattered coastal areas of Hawke’s Bay, Wairarapa and Central Otago.

Temperature

Mean temperatures were above average in parts of Northland. However, they were below average throughout the lower North Island, as well as in Buller, north Westland, and eastern South Island regions from Marlborough to Southland. Mean temperatures were more than 1.0°C below average in parts of Horowhenua, Kapiti, Wairarapa, Marlborough, and inland Southland. Temperatures were near average elsewhere.

Sunshine

Sunshine hours were at least 120 percent of average in parts of Northland, Auckland, Nelson, Westland, inland south Canterbury, Southland, and Otago. New April records totals occurred in Northland, Auckland, Nelson and Dunedin. It was also sunnier than average in most other regions. Hours of bright sunshine were near average in South Taranaki.

Full report

Full details of April 2005 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.