September was a month of weather extremes, but overall it was drier and slightly warmer than usual in Wanganui, according to statistics released this week by Niwa.
Georgina Griffiths, Niwa climate scientist, said westerly winds dominated New Zealand's weather during September, resulting in a drier east coast and wetter west coast than usual. The area between Wanganui and Wellington was the exception to this.
"For Wanganui, this September was drier [and likely sunnier] than usual, with temperatures about typical for the time of year for the month overall. However, there were large temperature swings - even for spring, when changeable weather is common," Ms Griffiths said.
She said an extended warm period was observed September 1-9, then a large southerly change produced a notable cold spell between September 11-13, and then the last two days of the month were fairly warm.
The highest temperature for the month was 19.6C, recorded on the 26th, while the lowest temperature for the month, a chilly 3.1C, was experienced just a few days earlier on the 22nd.
Ms Griffiths said just 55mm of rain fell in Wanganui - 75 per cent of the September average. Sunshine hours were not recorded in Wanganui but it was likely that it was sunnier than usual, since other sites on the west coast of the North Island registered more sunshine hours.