MOSES LAKE — Summer officially started Sunday, and it’s going to celebrate its arrival with temperatures that are about as summery as possible.

Temperatures are forecast to be 95 degrees and hotter all week, with triple-digits expected Friday and the weekend. The blast furnace temperatures may linger into early next week. The forecast high for Friday is 102 degrees. It’s projected to get even hotter Saturday and Sunday, with 108 degrees the forecast high on Sunday.

Jennifer Simmons, meteorologist at the National Weather Service in Spokane, said that’s about 20 degrees warmer than normal for the last week of June.

“We do have above-average temperatures (forecast) through the beginning of July,” Simmons said.

The cause is hot air blowing up from the southwest, and high pressure building in.

It’s “a dry, hot pocket of air that’s just going to be sitting over our region,” Simmons said.

Not that it helps, but most of the Pacific Northwest is going to be hot, from Portland to Boise to Spokane. The exception is the Puget Sound area, where temperatures are forecast to be in the mid-80s through the weekend.

High temperatures can cause problems for humans and animals alike. The Washington Department of Health recommends staying indoors under air conditioning as much as possible. If the building doesn’t have air conditioning, it’s best to stay on the lowest floor, out of the sun. Windows that get sun benefit from an awning or some kind of shade.

Water is a good thing on a hot day. People should drink plenty of fluids, but avoid beverages with alcohol, caffeine or a lot of sugar.

Pets, too, should have plenty of fresh water.

Families and friends should make arrangements to check on elderly or ill residents and friends. And elderly or ill people should make arrangements to be checked on.

Strenuous activity should be reserved for the early morning or late in the day, when temperatures have started to drop. Frequent breaks are a good idea if working outdoors.

Dizziness, nausea and muscle cramps are among the symptoms of heat exhaustion. The first step is to move to a cooler location, rest and drink a cool beverage. Immediate medical attention is necessary if symptoms persist.