"It's remaining much the same on Thursday and Friday, with some cloud and scattered showers."
Whanganui is also set to see a drop back to more standard temperatures towards the middle of the week, after a somewhat warmer Sunday and Monday.
"The biggest thing is that once this front moves east on Tuesday, the most humid air starts to move off. For example, Whanganui on Monday was quite warm. Overnight especially was warm, but that should ease off by Tuesday."
Looking towards the weekend, the seven-day forecast has both Saturday and Sunday looking much the same, with rain expected on both Saturday and Sunday.
"Put simply, it'll be a pretty dull week overall, with some cloud and rain. It's a pretty messy situation - not a very clear-cut one," Clark said.
Whanganui is looking at a high of 19C on Monday, with spots of rain, clearing by the evening.
For Tuesday, a high of 19C is also on the cards, with only a chance of showers during the day.