Wednesday is the first official day of summer, the first day of summer vacation for Needham students and the first really hot day of the season.

The National Weather Service has issued a Heat Advisory for Wednesday, June 20 for Needham and Norfolk County, as well as other parts of Massachusetts, Connecticut and Rhode Island. The advisory is in effect from noon to 7 p.m., with an anticipated high around 96 degrees in Needham.

"Heat indices up to 103 [degrees] will result in dangerous conditions for those spending prolonged periods of time outside," the National Weather Service advisory states. "[...] Hot temperatures and high humidity will combine to create a situation in which heat illnesses are possible."

The advisory recommends that people avoid working outside for long periods of time or in poorly ventilated areas, stay out of the sun and in air-conditioned places when possible, drink plenty of fluids and check on relatives and neighbors who may be especially vulnerable to the heat.

"The Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments" for those working outdoors," the advisory states. "Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency—call 9-1-1."

For other tips on staying healthy in the summer heat, check out this 2011 article from the Needham Public Health Department.

The hot weather is expected to stick around for a couple of days, with a high near 97 degrees on Thursday and a high near 89 on Friday.

Looking to cool off? Needham's Rosemary Pool is open daily from 12:30-7:45 p.m., unless there is thunder or lightning in the area. Admission is $6 per day for Needham residents or $8 for non-residents, with half-price admisison after 6 p.m. Seniors age 60 and over receive a reduced rate.