EVERETT — Time to dig out the SPF 50 that’s been collecting dust since September.

An unusually cold and rainy spring made it seem like it might never happen, but summer is here and things are heating up in Snohomish County.

The first heat wave of the year will hit Snohomish County starting Saturday, the National Weather Service announced this week. The agency issued a heat advisory for nearly all of Western Washington from noon Saturday to 11 p.m. Monday.

Forecasters expect temperatures to reach around 90 degrees, a far cry from the last few weeks which saw highs averaging in the low 60s.

The heat wave will continue through Monday according to forecasters. National Weather Service meteorologist Kirby Cook said temperatures will “start to creep up into the upper 70s” on Friday. Sunday will be the hottest day, Monday a close second. Relief in the form of a “big cooling” is likely to come on Tuesday, he said.

The National Weather Service warned of a “moderate risk” of heat-related illnesses for heat-sensitive people and pets.

Fifteen people died due to heat-related causes in Snohomish County during the scorching 2021 Pacific Northwest heat wave, when temperatures reached triple digits. That extreme heat event ran from June 26 to July 2, 2021.

The Snohomish Health District encouraged people to be aware of the signs of heat stroke and heat exhaustion and to check on at-risk people, including older adults, infants, young children and pregnant people.

Cook said the cool weather this spring means people may be especially unprepared for the upcoming heat. “People are probably not used to it, so it’s going to be a bit of a jump into a pretty warm weekend.”

He stressed the importance of staying hydrated and suggested people seek out places with air conditioning, such as movie theaters and grocery stores.

Snohomish County has 23 designated cooling centers where people can stay cool during extreme heat events.

Nature’s cooling centers, the rivers and streams of the Pacific Northwest, are always enticing on hot days. But folks planning on beating the heat by taking a dip may want to think twice. Waterways are colder, higher, and moving faster than they normally are this time of year thanks to the cool and wet spring weather, Cook explained.

“It might be tempting to jump into whatever body of water you’re next to, but you really need to be cautious about that,” he said.

The weekend’s heat wave is a dramatic departure from the cold, clouds and rain of the past few months. But it doesn’t mean the gray is gone for good.

“It looks like we’ll trend back to cooler-than-normal,” Cook said of the forecast for July.

Natalie Kahn: 425-339-3430; natalie.kahn@heraldnet.com; Twitter: @nataliefkahn.