Get ready to swelter.
Excessive heat and humidity are expected for Thursday, Friday, and maybe Saturday.
Boston Mayor Martin J. Walsh declared a heat emergency for the three days, saying the city was opening Boston Centers for Youth & Families facilities for use as cooling centers beginning Thursday.
Highs in the 90s are expected for all three days in much of the state, with some areas even climbing to the mid-90s Thursday.
The heat index, which combines both temperature and humidity, will reach 100 to 105 degrees in Eastern Massachusetts on Thursday, officiaRls said. The South Coast and the Cape and islands are likely to be cooler.
The National Weather Service issued a heat advisory for much of Eastern Massachusetts for noon to 7 p.m. Thursday.
“The combination of hot temperatures and high humidity will combine to create a situation in which heat illnesses are possible,” the forecasters warned.
The Massachusetts Emergency Management Agency also warned of the heat, as well as showers and thunderstorms Friday through Monday, with the highest risk of localized flooding on the weekend.
Here are some of the tips officials are offering to survive the heat:
• Stay hydrated
• Check on elderly neighbors who may be at risk of heat stroke
• Avoid strenuous activity during the heat of the day
• Secure air conditioning units
• Children should wear shoes on playgrounds to avoid burns
• Don’t light outdoor fires
• Wear lightweight clothing
• Take frequent breaks when working outside
• Don’t leave children or pets alone in vehicles, even for a short time.