The showers may turn to rain later today and overnight in Auckland.
In the South Island most of the rain will be falling on the West Coast, with isolated showers in other areas including Nelson, Southland, Otago and a spot of rain in Canterbury.
"All in all it is not looking too bad," Dyason said.
"Temperatures will be nice and warm with the warm air mass.
"Up north will probably feel quite humid today and tomorrow, but it is likely not to be as bad as in early February.
The dew point would be in the upper teens. During the sleep-depriving humidity of early February it was 22-23C.
Things won't change a lot for the weekend, Dyason said.
"The driver of all of this is a high to the southeast and blocking a low to the west.
"Instead of the low moving over, it is just moving closer and weakening. There is also another smaller low to the north.
"It is slow-moving, so those showers in the north will likely stick around to the weekend.
"It is the same in the south. Rain will continue on the West Coast through to the weekend, and there will be showers in the east.
But temperatures will be warm. South Island will be in the early 20s and the North Island in the mid 20s.
Today's weather
Whangarei: Humid and mostly cloudy, with a few showers. Rain at night. Northeasterlies. 25C high, 20C overnight.
Auckland: Humid and cloudy with a few showers, turning to rain in the evening. Northeasterlies. 25C high, 20C overnight.
Hamilton: Mostly cloudy. The odd shower from late morning. Northeasterlies. 24C high, 18C overnight.
Tauranga: Cloudy, with a few showers. Northeasterlies. 23C high, 20C overnight.
New Plymouth: Cloud increasing, and the chance of a shower from afternoon. Northeasterlies. 25C high,
17C overnight.
Napier: Fine, with high cloud. Northeasterlies. 25C high, 18C overnight.
Wellington: Partly cloudy. Light winds. 23C high, 17C overnight.
Nelson: Often cloudy, with the chance of a shower, rain developing at night. Northeast breezes. 23C high, 17C overnight.
Christchurch: Fine with high cloud. Northeasterlies. 24C high, 15C overnight.
Dunedin: Overcast with occasional rain in the morning. Northerlies. 23C high, 16C overnight.