A heat wave is hitting Boston. Here are tips on how to stay cool and safe

Summer officially begins Thursday, and is there a more fitting way to greet the sunny season than with a heat wave?

Starting Tuesday and continuing through Friday evening, nearly all of the region will face an official heat wave, with temperatures over at least three consecutive days exceeding 90 degrees. The National Weather Service issued a heat advisory for most of Massachusetts.

The oppressive heat is part of a larger wave hitting huge swaths of the country, from Iowa all the way up to Maine. Combined with humidity, Massachusetts residents could see heat index values reach 105 degrees.

Boston Mayor Michelle Wu declared a heat emergency Monday that runs from Tuesday until Thursday. Here's what you should know to stay safe and cool through the worst of the wave.

Gov. Maura Healey also advised residents to take precautions during the heatwave.

"With several straight days of hot and humid weather expected this week, it's essential that Massachusetts residents make a plan to stay safe — including keeping hydrated, limiting strenuous activity and checking in one another," she said in a statement.

Her office recommended the following checklist:

Boston residents who need help staying cool can head to cooling centers at 14 Boston Centers for Youth & Families, which will be open Tuesday and Thursday from 9 a.m. to 5 p.m. There will be programming for children under 5 at the centers, Wu said in a statement. Keep in mind that the centers, Boston Public Schools and the Boston Public Library will be closed on Wednesday for Juneteenth.

This year, the city is launching other new cooling initiatives, including setting up outdoor misting towers at fire stations and parks during heat emergencies, as well as the city's Open Streets events.

The Office of Emergency Management will also distribute pop-up cooling kits with misting tents during heat emergencies and at outdoor events hosted by the city and community organizations, Wu said.

Pools and splash pads throughout the city will be open for residents to use. However, some of the pools are undergoing maintenance or repairs and are not open, so be sure to check before you go.

Mass. residents also can take full advantage of Department of Conservation and recreation's 81 waterfronts and spray parks across the state, as well as saltwater ocean beaches and freshwater inland beaches.

In her statement, Wu said that the 10 Boston schools without air conditioning will have a surplus of fans available, and bottled water available on site.

She asked parents to dress their children appropriately and said school leaders have been instructed to move outdoor activities indoors.

The Animal Rescue League of Boston also reminds pet owners to keep their furry friends safe during extreme heat. High humidity can also cause respiratory issues for animals, particularly short-snouted animals like pugs.

The group recommends the following:

It's illegal in Massachusetts to keep an animal confined in a vehicle during extreme hot or cold conditions and whenever a weather advisory is in place, the group stressed. It's also illegal to keep dogs tethered for longer than five hours within a 24-hour period.

Bostonians in need of support during the heat wave can call the city's helpline at 3-1-1 or find resources at boston.gov/heat.

Residents across the state can call 2-1-1 to find nearby cooling locations or shelters, Healey's office said.

With additional reporting from WBUR's Zeninjor Enwemeka