"The region can look forward to calmer weather for the next few days although a southerly change will lead to a cooler day on Monday."
Best said the temperature forecast was for a high of 14C with an overnight low of 7C.
"The southerly is expected to die out later in the day and Whanganui can expect warmer temperatures for the rest of the week," he said.
Tuesday's forecast is for morning cloud followed by a mainly fine day with light winds and a high of 16C.
Wednesday is expected to be fine at first, followed by thickening high clouds and a few spots of rain later in the day, and light northerly winds. The temperature is expected to reach 17C.
The predicted high for Thursday is also 17C and the northwesterly will continue, with the cloud expected to linger.
Clear skies will be back in Whanganui on Friday and Saturday, with fine conditions forecast for both days and an easterly change on Saturday.
A high of 17C is forecast on Saturday and Sunday although Sunday is expected to be partly cloudy with light winds.