SEATTLE - It's a June and early-July ritual along the entire Pacific Coast -- being socked in with fog while areas just a short drive inland are basking in the summer sunshine. But it's that summer sun that causes the coastal fog.
The Pacific Ocean stays pretty cold up here -- around 55 degrees -- in the summertime, which keeps the air right near the water cooler than over land. As the warm sun shines on the ocean, water will evaporate, and then quickly condense amid the cool air and form a low overcast or fog bank. The fog will drift inland just a bit since the immediate coastline also stays cool from the nearby ocean.
If we have a westerly flow, the winds will bring those low clouds inland to the Puget Sound region -- aptly named a marine push.