As a heat wave engulfs the state, all Wareham town buildings will be open to the public as cooling centers during regular business hours, the town announced Tuesday afternoon. 

Much of Massachusetts will be under a heat advisory from about 11 a.m. to 8 p.m. on Wednesday, according to the National Weather Service. The heat index, the summer’s version of wind chill during the winter, is expected to reach up to 99 degrees, per the service.

The heat and high humidity could cause heat illnesses, the National Weather Service warns. It encouraged residents to drink plenty of water, stay out of the sun and check in on relatives and neighbors.

The auditorium in Town Hall will be open from 8 a.m. to 7 p.m. Tuesday through Thursday, available for residents who need to get out of the sun and cool down. The town will announce cooling center times for the weekend at a later time, a town announcement said.