A fine day is being forecast for the Bay of Plenty today.

It was a cool start, with 4 degrees recorded around 6.30am.

It is expected to get up to about 15 degrees today, with an overnight low of five.

Weatherwatch.co.nz says a southwesterly airflow tends northwest for the South Island today.

"A mix of sun and cloud in the west with a few showers, drying out this afternoon. Southwesterly winds," says a spokesperson for the weather organisation.

"Bay Of Plenty and the east coast has a sunny day although a few showers for Wellington and Wairarapa clear this morning. A frosty start for inland areas."

In the South Island, cloud thickens for the West Coast, the odd shower turning to rain about South Westland this afternoon then becoming heavy.

"In the east expect dry weather today with sun and increasing high cloud.

"Very frosty to start this morning about and east of the Main Divide."

Image: WeatherWatch.co.nz