Spring is usually "not a very forgiving season", according to MetService meteorologist Tui McInnes and Whanganui's weather this week will be a quintessential example of that.
"There's a low currently (Tuesday) sitting in the Tasman Sea, and Whanganui will increasingly see the signs of it throughout the day, unfortunately," McInnes said.
"There will be a general deterioration in the sunshine and the clouding over will be a foreshadowing of what's to come. We'll see increasing periods of rain as we go into the evening and through to Wednesday morning.
"Wednesday will bring periods of rain, with a risk of thunderstorms to the north. There's unlikely to be thunderstorms in Whanganui itself, but the flow-on effect is the chance of a few heavier showers."
McInnes said Thursday would bring a brief respite from the "showery, wet conditions", although skies would remain cloudy.
"It'll clear a bit as we go into Friday, but bursts of southerly winds could cool things down and bring a few more showers. In a nutshell, it'll be more rainy in the middle of the week, and more windy towards the end of the week."
Weekend weather would continue to be patchy, McInnes said.
"Westerly winds come back and things start to get cloudy, with, you guessed it, rain approaching.
"It's that 'flip-flopping' spring nature, where you go 'here's some low rain, oh great', then there's a southerly change, then 'oh cool, it's clearing', then 'nah, just joking, here's more rain'". It's Mother Nature playing a joke on us."
While the weather would be inconsistent for the next few days, McInnes said temperatures would remain steady, from the "high teens to low twenties".
"Even the overnight temperatures aren't too bad," McInnes said. "I suppose that's your silver lining."