September 2007

• Rainfall: Below normal in many areas, near or above normal in the parts of Northland, east of the North Island, parts of Otago and Fiordland.
• Temperature: Above average in the north of the North Island, and parts of the South Island.
• Sunshine: Above average in the south west of the North Island, western and inland
• Wind: Less wind than normal

September 2007 was a relatively benign month with more anticyclones and less wind than normal, and less extremes. This resulted in less rainfall than normal in many areas, especially the west of the North Island. Temperatures were above average in many North Island areas.

Rainfall was less than 50 percent (half) of normal in Taranaki, Wanganui and Manawatu, Westland, Marlborough, Banks Peninsula and the Catlins. Soils were drier than normal in eastern Marlborough and north Canterbury. Temperatures were above average in the north of the North Island and the west of the South Island.  The national average temperature of 10.5 ºC was 0.1°C above average. The month was sunny in the Manawatu, Kapiti, Westland, inland areas of the South Island and Dunedin, but cloudy in Northland. September’s climate patterns were produced by more anticyclones (‘highs’) over New Zealand and to the south and east, resulting in lighter winds than normal, but with more easterlies over the north.

Further Highlights

• The lowest air temperature during the month was -6.0ºC recorded at Fairlie on the 6^th and Hanmer on the 7^th, following cold southerlies early in the month. A grass minimum of -10.9 ºC was recorded at Mt Cook Village on the 7^th and 11^th.
• The highest temperature during September 2007 was 24.0  ºC recorded at Wanganui Airport on the 20^th, the highest temperature recorded at that site.
• High rainfall at Kaitaia totalled 102 mm over 24 hours to 9am on the 19^th.
• Snowfall occurred to low levels in the east of the South Island on 4 September , settling in low lying parts of Canterbury (6-8cm) in and around Ashburton, Methven, and Geraldine.
• Of the five main centres, Auckland was the warmest and wettest, Christchurch the driest and coldest and Wellington the sunniest.

Rainfall

Rainfall was about 50 percent (half) of normal in the west of the North Islands from Taranaki to Manawatu, as well as Marlborough, Banks Peninsula and the Catlins. Rainfall totals were less than 75 percent (three quarters) normal in many other areas. Normal or above normal rainfall was confined to northern Northland, Gisborne, the Strath Taieri in Otago and Fiorldand.

Temperature

Mean temperatures were about 0.5 to 1.0 ºC above average in the north of the North Island the west coast and inland parts of the South Island. The national average temperature was 10.5 ºC (+0.1°C above average).

Sunshine

September sunshine hours were at least 120 percent of normal in Manawatu, Kapiti, Westland, inland South Canterbury and Dunedin. Sunshine hours were below normal in Northland and Waikato and slightly above normal elsewhere.

Full report

• Full details of the September 2007 Climate 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.