Winds are expected to be light southeasterlies throughout Friday.
“The unfortunate news is that that does change slightly heading into Saturday.”
The winds will shift to westerlies on Saturday and Sunday, bringing cloud and scattered showers as a front moves up from the south.
Lyons said Saturday would be the worst weather day of the weekend.
“There’s going to be a bit more cloud pushing in and some showers for the Whanganui area as well.”
Into Sunday, Lyons said the wet weather “somewhat clears out”.
“The showers are not quite as intense, as frequent as they would be on Saturday, but they are still around as well as some of that cloud.”
The daytime high temperatures are expected to be 23C on Friday and 24C on Saturday and Sunday.
Overnight lows are forecast of 15C on Friday, 16C on Saturday and 15C on Sunday.
“Friday, Waitangi Day, is really the day if you want to be outside and take advantage of the sun.
“It’s likely that on Sunday you could still catch some good times to do stuff outside.
“Saturday, a bit less so.”
Erin Smith is a multimedia journalist based in Whanganui.