- Rainfall: Extremely low in the east from Wairarapa to Otago; above average in Fiordland and coastal Southland
- Significant soil moisture deficits in Central Otago, deficits developing in other eastern regions
- Temperature: Above average, especially in the east from Marlborough to Central Otago
- Sunshine: sunny in Gisborne, Otago, and inland South Canterbury
- Very windy in the south of the South Island
September was a month of climate extremes with record low rainfall and high mean temperatures at many locations. Rainfall was low throughout much of New Zealand, especially in the east from Wairarapa to Canterbury, some Canterbury locations recording 10 percent (one tenth) or less of normal rainfall. There was about 10 mm or less in some parts of Marlborough, Canterbury and Otago. The low rainfall has resulted in the development of significant soil moisture deficits (110 mm or more) in Central Otago. Soil moisture deficits, although not major, also exist as far north as Marlborough. It was the third warmest September on record, with the national average temperature being 11.6°C, 1.2°C above normal. Temperatures were above average throughout New Zealand, especially in the east from Marlborough to Otago where they were about 2.0°C above average producing new records of mean temperature. Maximum temperatures exceeded 20°C in many eastern regions from 21 through 26 September. Sunshine hours were above normal over much of New Zealand, especially in eastern regions. In contrast, in was unsettled and much windier than normal in Fiordland and along the Southland coast, the only districts where September rainfall was above normal. More anticyclones (‘highs’) predominated over the Tasman and across the North Island, with below average pressures well south of New Zealand. This pattern produced much stronger westerlies than normal over the South Island, and more frequent strong winds than average in Wellington, South Canterbury, Otago, and Southland.
Other Highlights
- The highest temperature during September 2006 was 25.0°C recorded in Napier on the 22nd. Near or record high September air temperatures were recorded in Dunedin Airport (24.9°C), Invercargill (23.1°C) and Queenstown (24.3°C) on the 25th, and at Gisborne (24.9°C) on the 26th.
- The lowest air temperature for the month was -5.6°C recorded at Hanmer Forest on the 11th.
- A wind gust of 180 km/h from the northwest was recorded at Southwest Cape (Stewart Island) on the 2nd, a new record for a wind gust at that site (measurements commenced in 1992).
- High rainfall affected the southwest of the South Island over the 1st, 4th-5th, 15th, 18th-21st, 23rd, and 25th of September. Heavy rainfall totalling 294 mm was measured at Milford Sound from the 18th-21st. High rainfall also affected the North of the North Island on the 9th and 10th.
- Christchurch was the driest, Dunedin the sunniest, and Auckland the wettest of the main centres. Rainfall was below normal, and temperatures above normal in all five main centres. It was extremely warm and dry for the time of year in Christchurch. Sunshine hours were near normal in Wellington, and above normal in the four other main centres, with record values in Dunedin.
Rainfall
September rainfall was extremely low, being 10 percent (one tenth) or less of normal in parts of Canterbury, and 25 percent (quarter) or less of normal in Waikato, Southern Wairarapa, Marlborough, and North and East Otago. In many of these locations it was the lowest September rainfall on record. Rainfall was also well below normal in many other parts of the North Island, as well as Nelson. In contrast, Fiordland and the Southland coast were the only districts where rainfall was above normal, by as much as 50 percent.
Temperature
Mean temperatures were about 2.0°C above average in parts of Marlborough, Canterbury, and Otago, and more than 1.0°C above average in parts of Wairarapa, Hawke’s Bay, Kapiti, Wellington, Nelson, and Southland. Temperatures were also above average in most other regions.
Sunshine
Sunshine hours and/or solar radiation were at least 120 percent of normal in Gisborne, inland South Canterbury, and Otago. It was also sunny in Northland, Auckland, Waikato, Bay of Plenty, Napier, Marlborough, Nelson, and North Canterbury.
Full report
- Full details of the September 2006 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.