Say it with me: “It’s not the heat, it’s the humidity.’’

OK, it’s the heat too, and today promises to be another scorcher, Day 3 of the first real heat wave of summer.

But it is already better than it was on Sunday for most of the region. A heat advisory and an unsafe air quality alert have both been canceled for today.

A weak cold front will move across the region later today, resulting in isolated thunderstorms into the early evening, the National Weather Service says. Humidity and the heat index — the measure of how the heat and humidity combined actually feels, will be lower.

Temperatures will reach into the mid-90s inland and the upper 80s along the shore, the National Weather Service says. With the cold front moving through tonight, drier air and temperatures in the mid-60s should make for good sleeping.

There is a chance of thunderstorms early Tuesday, then skies will clear and the rest of the week will be sunny and seasonable, with daytime highs in the upper 70s along the shore and low 80s inland, and in the upper 50s at night.

But first, we have to get through today. Heat waves are dangerous, killing more people, on average, than any other extreme weather event, according to a fact sheet from the New York City Health Department.

Those most at risk are the elderly, people with chronic conditions including heart disease, obesity, asthma and other respiratory ailments. Alcohol and drugs can exacerbate the risks from extreme heat, the NYC health department says.

Those affected should drink plenty of water, stay indoors if possible and avoid exertion, the fact sheet says. Fans alone will not help; air conditioning dries as well as cools the air.

Sunday was a sauna for most area residents, with many communities opening cooling centers in public buildings for residents without air conditioning. A cooling station at the Greater Bridgeport Transit station downtown was open from 11 a.m. to 7 p.m.at 710 Water Street from 11:00 a.m. to 7:00 p.m.

About two dozen Bridgeport residents took advantage of the cooling stations provided by the city on Sunday, spokesman Tim Hammill said.

“The cooling stations are not open today, as we usually activate these locations during Air Quality Alerts or Heat Advisories,’’ he said Monday morning. “But residents who are looking for a cool place to avoid the heat can visit any of Bridgeport’s libraries, public buildings or the (bus) station today.’’

Bridgeport hit a high of 91 degrees at 1 p.m. Sunday; 99 on the heat index that factors in the humidity. Danbury had a maximum heat index of 94, 5 degrees higher than the actual temperature.

Newark, N.J. was the hottest place in the region, with a high temperature on 98 and a heat index of 103 on Sunday afternoon, the National Weather Service said.

The Bridgeport Emergency Operations Center (EOC) continues to monitor heat advisory and air quality alerts when they are issued by the National Weather Service, said Scott Appleby, director of. emergency operations.