The Bay of Plenty's reign of sunshine is coming to an end today with heavy rain and the chance of thunderstorms predicted this evening.

The MetService this morning issued a severe weather watch on the region as heavy rain is expected to hit the city this afternoon.

A front is moving up the country bringing a period of rain and strong southerlies to the North Island this evening.

MetService reports a trough ahead of the front together with daytime heating and humid conditions is likely to produce thunderstorms across the Bay of Plenty tonight. Humidity is currently at 86 per cent.

Heavy rain is also expected for the eastern Bay of Plenty ranges later today and early Tuesday bringing around 15-25mm/hr.

Strong wind gusts of up to 100km/h are also being predicted.

Police are also warning motorists to drive to the conditions with numerous crashes reported in the Waikato this morning.

Waikato police in Horsham Downs, Te Kowhai and Ngaruwahia responded to a number of crashes.

Temperatures are set to average 24 degrees this week with sunshine expected to return on Wednesday continuing through until next Wednesday, according to the MetService 10 day forecast.