May 2005

Rainfall: Record high rainfall in the Bay of Plenty

Temperature: Well above average throughout much of the North lsland, warm also in the north of the South Island

Sunshine: Above average in the south of the South Island

While record rains lashed Bay of Plenty in May, the South Island received above average sunshine. The month was very warm over the North Island and northern South Island. There were two extremely high rainfall – flood producing events in the Bay of Plenty region over 3-4 and 17-18 May, both affecting Tauranga, and the latter devastating the coastal township of Matata. Tauranga with 634 mm (695 percent of normal) had its wettest calendar month for any time of the year in more than a century, including its heaviest 1-day rainfall on record (347 mm on the 18th). It was also very wet in Coromandel and parts of Hawke’s Bay. Soil moisture surpluses occurred in Bay of Plenty, the south and east of the North Island and in Marlborough. The national average temperature for May was 11.4°C, 0.7 °C. May was very much warmer than usual in the North Island. However, temperatures were below average along the south Canterbury/Otago coast. Sunshine hours were well above average in inland south Canterbury and coastal areas of both Southland and Otago. However, they were below average in Waikato, King Country, along the Kapiti Coast, and in West Otago. During May, depressions ('lows') were often centred northwest of the North Island. Most anticyclones ('highs) occurred well away to the east or west of the country. More frequent northeasterlies occurred over the North Island and north of the South Island, contributing to the very wet conditions over much of the North Island.

Other Highlights

  • The highest temperature during May 2005 was 23.6°C recorded at Henderson (Auckland) on the 2nd. The lowest temperature for the month was -6.7°C, recorded at Ranfurly on the 18th.
  • Of the four main centres Dunedin was the driest, and Auckland the warmest. Rainfall was below average in Dunedin, but above average in the three other main centres. Temperatures were above average in Auckland, Wellington, and Christchurch, and below average in Dunedin. Sunshine hours were above average in Dunedin and near average in the other main centres.

Rainfall

Rainfall was at least 250 percent of normal in Bay of Plenty. It was also very wet in Coromandel and parts of Hawke’s Bay with totals of at least 200 percent of normal. Rainfall was also above normal in Auckland, Waikato, Taranaki, Gisborne, Wellington, Marlborough, and parts of Northland and north Canterbury. Totals were less than 75 percent of normal in parts of Buller and Otago.

Temperature

May was very much warmer than usual, with mean temperatures 1.0 to 1.5°C above average over much of the North Island, as well as much of Marlborough and Nelson. The largest anomalies were in the central North Island, where mean temperatures were about 2.5°C above average. Temperatures were also above average in Buller, Westland, and north Canterbury. They were below average along the south Canterbury/Otago coast.

Sunshine

Sunshine hours were well average in inland south Canterbury and coastal areas of both Southland and Otago. However, they were about 80 percent of average in Waikato, King Country. It was also sunny in coastal Otago. Totals were below average in Waikato, King Country, along the Kapiti Coast, and in West Otago.

Full report

Full details of May 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.