New figures have shown how September soaked much of New Zealand with as much as one and a half times the month's normal amount of rainfall.

But despite what seemed to many as a constant downpour, few places saw record rainfall, which Niwa scientists put down to a steady month of rain rather than freak events.

Official statistics released today show rainfall was "well above normal" - as much as 149 per cent of the September normal - or "above normal", which is 120-149 per cent of normal, for large swathes of the North Island.

That included much of Waikato, western Bay of Plenty, Auckland, Manawatu-Whanganui, parts of Gisborne and Hawke's Bay, much of the northern half of the South Island, along with eastern Otago and western Southland.


"However, despite the fairly widespread above- to well-above normal rainfall, there were relatively few locations that received monthly or one-day rainfall records and near-records," Niwa reported in its climate summary.

"This indicates that the rainfall in September was more the result of regular, moderate events versus heavy, extreme events."

A notable exception was at Hanmer Forest, which received its highest one-day September rainfall - 126 mm - on the September 18. Records date back to 1905.

It was also a notably wet month on Stewart Island, where the South West Cape recorded its wettest September since records began in 1991.

The only regions that received less rain than normal was central and southern Hawke's Bay, central Otago, and eastern Southland.

Temperatures meanwhile hovered around average across most of the country, but were slightly warmer than usual for Auckland, Coromandel, northern and central Waikato, Gisborne, Hawke's Bay, southern Manawatu-Whanganui, northern Marlborough, northern Canterbury, and much of Otago.

Sunshine hours were also near normal for much of the country - parts of Waikato and northern Manawatu-Whanganui even got more than their usual share.

"Despite September being a wet month for many, frequent breaks in the wet weather also brought many partially sunny days," Niwa stated.

"The swing between sun and cloud throughout September evened out so that overall the total sunshine hours were near normal for much of the country."

September's weather was coloured by lower than normal sea level pressure over the Tasman Sea and New Zealand, which resulted in regular bouts of rainfall moving across the country.

That included enough heavy rain on September 6 to trap two tourists in their car in Waitomo.

After the wet start to spring, MetService has predicted a warmer-than-usual October is also predicted right across the country.

Fine weather was forecast to favour both islands equally, but towards the end of the month, this would change to a focus on the south as easterly winds set up over northern New Zealand.

And although most of the country will have a drier than normal October, northeastern parts of the country should get average rainfall, MetService reported.

September: Highs and lows

• The highest temperature was 26.6C, observed at Christchurch (Riccarton) on September 15 and 25, and at Hastings on September 25.
• The lowest temperature was -6.4C, observed at Mt Cook Airport on September 4.
• The highest one-day rainfall was 126 mm, at Hanmer Forest on September 18.
• The highest wind gust was 154 km/h, at Akitio on September 25.
• Of the six main centres, Auckland was the warmest, Christchurch and Dunedin were the coldest, Hamilton was the wettest, Dunedin was the driest, Tauranga was the sunniest, and Christchurch was the least sunny.
• Of the available, regularly reporting sunshine observation sites, the sunniest spots so far are Whakatane (1815 hours), Blenheim (1792 hours), Richmond (1790 hours), and Napier (1744 hours).