September 2004

Rainfall: Well below average in Northland and Hawke’s Bay; above average in Central New Zealand and some eastern South Island districts

Temperatures: 3rd consecutive month with below average temperatures

Sunshine: Above average in many eastern regions

September was dominated by cold southwesterlies. Rainfall was well below average in North Island areas sheltered from these, with the development of significant soil moisture deficits on the Kaikoura Coast. In contrast, above average rainfall occurred in the southwest of the North Island, as well as Marlborough, Nelson, the Southern Alps, and some eastern districts from Banks Peninsula to Southland. The month was unsettled, with several more wet days than average, in Westland, Fiordland, Southland and Central Otago. Temperatures were below average throughout much of New Zealand for the 3rd consecutive month. Sunshine hours were above average in many eastern regions, as well as the southwest of the North Island. Depressions (‘lows’) were very frequent well to the southeast of New Zealand, with anticyclones often centred in the Tasman Sea. This produced more frequent southwesterly airflow over New Zealand..

Highlights

• The highest September 2004 temperature was 24.0°C, recorded at Woodbury on the 21st. The lowest temperature for the month was -8.0°C, recorded at Snowden (Canterbury) on the 29th.
• Snowfall and low temperatures occurred in inland areas of Southland and Otago on the 18/19th, and in inland areas of Canterbury on the 28th, with a loss of newborn lambs from exposure. Snowfall on the 28th also occurred on the Desert Road, the Rimutaka Hill Road, SH1 between Kaikoura and Cheviot, and most South Island high country passes.
• The same weather system that brought snowfall to Canterbury on the 28th also produced high rainfall and surface flooding in parts of Manawatu.
• Of the four main centres Wellington was the sunniest and Christchurch the driest. Rainfall was below average in Auckland, Christchurch, and Dunedin, but above average in Wellington. Temperatures were near average in Dunedin, but below average in the other three main centres. Sunshine hours were above average in Wellington and Dunedin, and near average in the other two main centres.

Rainfall

Rainfall was less than 50 percent (half) of average in inland and eastern Northland, Gisborne, Hawke’s Bay, and the Kaikoura Coast. Totals were also below average in Auckland, Coromandel, Wairarapa, Tongariro-Ruapehu, and the region in and around Wanaka. Rainfall was above average in the southwest of the North Island from Wellington to Manawatu, as well as Marlborough, Nelson, the Southern Alps, Banks Peninsula, coastal areas of South Canterbury and north Otago, and Southland.

Temperature

Mean temperatures were below average throughout much of New Zealand, but near average on the Kaikoura Coast and in coastal areas of Otago. The national average of 10.0°C was 0.4°C below average.

Sunshine

Sunshine hours were above average in Gisborne, Hawke’s Bay, Kapiti, Wellington, Marlborough, and Nelson, and near average in most other regions.

Full report

Full details of September 2004 summary.

Acknowledgement of NIWA as the source is required.