Apart from some early-morning clouds and mild southeasterly breezes, Whanganui is in for a fine last day of summer on Monday.
A high of 21C is forecast with an overnight low of 10C, and sets a pattern for the next seven days.
"It's due to a high-pressure system over the region," MetService meteorologist Tuporo Marsters said.
"It's keeping the west coast sheltered while there's a bit of rain over on the east side. It promises a fine and settled week for the Whanganui region, but it doesn't make for very exciting weather news I'm afraid."
Autumn begins with a fine morning on Tuesday expected to reach a high of 23C, with some afternoon cloud and light southeasterly winds.
Highs of 23C are also forecast for Wednesday, Thursday, and Friday, with overnight lows of 9-10C.
The fine weather is expected to continue into the weekend with a high of 24C and an overnight low of 11C forecast for Saturday. The day will be partly cloudy with light winds.
The days are now becoming noticeably shorter with the sun rising at 7am and setting at 8pm.