Winter 2012 was a season of two halves, according to figures released this week by Niwa.
Climate scientist Georgina Griffiths said winter started colder than usual but ended unusually warm.
In Wanganui, it was slightly drier than usual - 216mm of rain fell between June and August, compared to the average 249mm.
"This is 87 per cent of normal winter rainfall in Wanganui," Ms Griffiths said.
July saw both the highest and the lowest temperatures for Wanganui's winter. The coldest was -1.1C, on July 1, while July 30 saw the warmest temperature of 18.3C.
Ms Griffiths said Wanganui's mean temperature for winter was slightly above the average of 10.0C, at 10.3C. Sunshine hours were also slightly above average, along with the rest of western areas of New Zealand.
She said winter 2012 was characterised by much higher pressures than normal to the south-east of New Zealand, and extending across the South Island.
"However, the season started off with frequent south-west winds over the country, resulting in a cooler and drier than normal start to the winter. In the middle of July, a change to more frequent north-east winds brought relatively mild and rather wet weather to many areas."
Niwa is forecasting an average spring.