A heat advisory and excessive heat watch remain in effect for the week, as the mercury continues to climb to 90 degrees and above.

The first day of summer on the calendar is Thursday, but the season is already here.

Sunny, hot and humid weather is on tap today with a high of 90 degrees, and Wednesday, Thursday and Friday bring more of the same with some clouds and high temperatures in the low 90s.

Saturday could be the first day of the week with high temperatures only in the high 80s, but AccuWeather meteorologist Tom Kines isn’t ruling out a 90-degree day.

“Not a whole lot has changed and we stay hot through the weekend, or at least until the end of the weekend,” he said. “It looks like early next week the heat will finally get out of here, at least for a couple of days and temperatures get back to where they should be.”

People could see an evening or afternoon thunderstorms Friday and Saturday with the heat and humidity continuing.

The heat could return as soon as late next week or the start of the following week, Kines said.

“But we should get at least a couple of days of relief the first half of next week,” he said. “And the humidity should get out of here.”

Kines suggested people should be thinking about taking it easy with this continuing heat, and sitting back and relaxing, and avoiding strenuous activities.

Staying cool indoors and out of the heat is always advised, he said.

“I think your best friend this week is going to have the initials A.C.,” Kines said. “The air conditioning is going be a huge help for people this week.”

The evening temperatures this week aren’t going to help, either, as people can expect low temperatures to remain at 70 or above, he said.

With the continued heat, people should slow down, stay hydrate and spend time indoors in an air-conditioned space, according to the American Red Cross of Greater Pennsylvania.

The heat is more than uncomfortable, it can also be deadly, especially for those with chronic medical conditions, the very young and older adults. More than 2,300 people died due to the heat across the country last year.

People should postpone or limit outdoor activities, including strenuous exercise, and those who must work outdoors should take frequent breaks and avoid the hottest part of the day by scheduling tasks earlier or later.

The Red Cross also advises people to drink plenty of water and avoid sugary, caffeinated and alcoholic drinks. They should also check that animals have access to plenty of fresh water and shade.

People should also try to spend time indoors in air conditioning, the Red Cross said. Those without air conditioning should go to a public library, a shopping mall or public cooling center.

Peaceful Knights Inc. in Lehighton will be keeping its men’s emergency shelter open 24/7 through heat wave. Family Promise of Carbon County will allow people to come inside its rectory building in Nesquehoning during the day, as work continues on the church, which will serve as a heating and cooling center.

The American Red Cross also advises people to be aware of the warning signs of heat-related illness, which can be prevented.

Among them are heat cramps, which includes heavy sweating and muscle pains or spasms. The person should be moved to a cooler place and encouraged to drink water or sports drinks, and get medical help if symptoms last more than an hour.

Heavy sweating is also a symptom of heat exhaustion, which is a more severe condition, the Red Cross said. Other symptoms are cool, pale, clammy skin; a fast or weak pulse, nausea or vomiting, muscle cramps, tiredness or weakness or headache, dizziness or passing out.

A person suffering from heat exhaustion should be moved to a cooler place, loosen any tight clothing and encourage them to sip water slowly, the Red Cross said. Also, use wet cloths, misting or fanning to help cool them off. People should seek help if symptoms worsen or last longer than an hour.

Finally, heat stroke is a deadly condition that requires immediate medical help. Symptoms include high body temperature, hot red, dry or damp skin, a fast or strong pulse, a headache or dizziness; nausea, confusion or passing out.