Wednesday is western Washington’s hottest day of the year so far, and the humidity is only making it worse

Western Washington won’t set any records, but Wednesday will be the hottest day of the year so far.

According to meteorologist Scott Sistek, Wednesday’s weather will also be muggy, partially due to last week’s thunderstorms. A lot of moisture is still in our plants, and when temperatures rise, the water evaporates and humidity spikes.

“Probably right around 92 to 94 in Seattle, so even a little warmer,” Sistek said on “Seattle’s Morning News.” “And I noticed that a lot of people are talking about it being a little muggier than we’re used to when it’s hot like this, so it’s been kind of everything. If you look ahead in the forecast, it’s pretty much got something for everyone.”

The humidity is additionally intense due to remnants of a tropical storm off Mexico.

“I think part of it was how wet it was last week with the thunderstorms in here,” Sistek said. “A lot of that water was still in the plants, and everything, and then the sun comes out, and it’s 90 degrees, and it’s evaporating all that. This is common in the Midwest. You hear about this a lot. It’s not quite the same as corn sweat — if anyone’s from Iowa, they hear that all the time — but in that distant relative process of, ‘It was wet, now it’s hot.’ It’s just dumping a lot of moisture.”

Once it cools down Wednesday night, the threat of lightning will ramp up, especially in the Cascades.

“It’s not good. The last thing we need is lightning,” Sistek said. “The worst is heat, but the second thing is ‘OK, we’re cooling off. Well, now the trade-off comes.’ Here come some thunderstorms. It is very dry up there. Some of these thunderstorms may not have a whole lot of rain with them. They may be dry thunderstorms. So that’s not good either. And we’ve got the lightning. We don’t have the water to wet things down.”

The all-time record high temperature for Seattle on July 22 was 96 degrees in 2006, two degrees higher than what today will bring. The typical high for July 22 is 78.

Air quality

Air quality will continue to be an issue across the Puget Sound Wednesday.

“We’ll get through today pretty smoky, almost similar to what we had yesterday,” Sistek said. “It’s a loft around here. It’s much worse in eastern Washington up in the mountains, and for western Washington, it’s hazy, but there’s not a whole lot of smoke near the ground, so the air quality is hanging in there.”