Saturday was hot, but Sunday could be worse.
A heat emergency warning has been in place in Boston since Friday noon and will continue into Sunday evening. Sunday's temperatures could be as high as 99, with heat index values near 105 degrees, according to the National Weather Service.
The heat index — which factors humidity and temperature — is how hot it really feels. Excessive heat can cause cramps, exhaustion and heat stroke. As of 11 a.m. Sunday, Boston Emergency Medical Services reported 21 patient transports because of heat-related illnesses.
On Saturday night temperatures in Boston didn't drop below 80 degrees.
WBUR meteorologist Dave Epstein says all this heat is being caused by high pressure acting as a big heat pump and pulling in tropical air. Late Sunday and into Monday, the high will begin to break down. There will also be the chance for a few thunder showers. Cooler and less humid weather will take over early next week.
City pools in Boston and some surrounding towns are waiving entrance fees to help people beat the heat. Community centers are acting as cooling centers for those looking for air conditioning.
On Saturday, Boston Mayor Marty Walsh encouraged people to be safe in the heat.
"We are asking people if you can stay in, stay in," Walsh said. "Stay cool, drink plenty of water, check on your neighbors, check on elderly housebound folks if you have any around your neighborhoods, don't do any excessive work in the yard. Be very slow with what you do."
This article was originally published on July 21, 2019.