The start of July brought a blast of hot air to the Seattle area with a record-high temperature of 94 degrees Tuesday.

At 5:40 p.m., at Seattle-Tacoma International Airport, the temperature recorded by the National Weather Service was 5 degrees higher than the previous July 1 record, 89 degrees, set last year, meteorologist Johnny Berg said.

It was also 5 degrees warmer than the weather service had forecast.

“Sometimes we get these little thermal troughs that end up a certain day, then it moves east and we get cool again,” Berg said.

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Throughout Western Washington on Tuesday, afternoon temperatures rose into the upper 80s and lower 90s, with several areas reaching or breaking records for July 1, the weather service said.

Quillayute tied its record of 91 degrees, Olympia reached 94, breaking its previous record by 6 degrees, and Bellingham set a record at 84 degrees.

A heat advisory was issued for Tuesday afternoon for areas of Southwest Washington, where temperatures reached the mid- to upper 90s.

Wednesday will be noticeably cooler, Berg said. The forecast is for sunny skies with a high of 79 degrees. The daily highs are expected to decrease through the week to the low 70s the Fourth of July, and rain is expected to stay away until this weekend.

The sunny skies and warm temperatures prompted King County officials to urge residents to exercise extreme care when they are near and in the water. The county advises wearing a life jacket and taking advantage of pools or local beaches that have lifeguards.

“Life jackets are to water like seat belts are to cars — standard safety equipment for the trip,” said Dr. David Fleming, director and health officer for Public Health — Seattle & King County.

Though the temperatures are warm, lakes, rivers and Puget Sound can still be extremely cold. Water in rivers fed by an above-average snowmelt is still below 50 degrees, while the temperature in Puget Sound and area lakes is not much warmer.

On Monday in Seattle, the water at Warren G. Magnuson Park Beach on Lake Washington was 66 degrees, and the water in Green Lake was 68 degrees, according to King County’s swimming-beach monitoring.

Paige Cornwell: 206-464-2530 or pcornwell@seattletimes.com