The visible satellite picture this morning says it all, Low clouds along the coast, with some of them pushing inland as far as Shelton and Portland. And smoke...lots of it... spreading as far south as Seattle, with dense smoke over southern Vancouver Island, the Strait of Georgia, Vancouver and vicinity. So if you don't like smoke, go south.
The morning cams from a variety of locations show the murk, particularly in southern BC (see below)
The smoke actually cooled the high temperatures down north of Seattle yesterday by reducing the amount of solar radiation. Here is a plot of the solar radiation measured at the University of Washington yesterday...and Seattle did not get the worst of it. On the left is July 4 and on the right is yesterday. See the difference? One is a smooth curve showing radiation under clear skies, the second has a number of dips and reductions due to the smoke.
First, a typical summer day.
The smoke season has begun over the Northwest and it will continue for a few months.