Seattle Weather Shifts from Near-90-Degree Heat to Days of Rain and Thunderstorms

Seattle will experience a dramatic weather reversal this week, transitioning from Tuesday's near-90-degree high to days of rain, clouds, and possible thunderstorms as cooler air moves into the region. The shift represents a significant change from the warmest day of the year so far, with temperatures expected to fall steadily through the weekend.

The Heat Before the Chill

Tuesday will mark the peak of the warm period, with some areas approaching 90 degrees as a strengthening ridge of high pressure and strong offshore winds drive afternoon temperatures upward. This will be the hottest day Seattle has experienced so far this year. However, the warmth is short-lived, as weather systems moving into the region will fundamentally alter conditions starting Wednesday.

Cooling Trend and Increasing Moisture

An upper-level low-pressure system positioned off the Washington coast will shift wind patterns to westerly by Wednesday, introducing onshore flow that brings cooler air and increased cloud cover. Wednesday's high will reach only near 71 degrees, a significant drop from Tuesday. Rain chances will begin to increase, with a 20 percent chance Wednesday night after 4 a.m. and stray showers possible throughout the day. By Thursday, highs will fall to around 68 degrees with continued cloudiness.

Friday will be even cooler, with temperatures remaining in the 60s and a 30 percent chance of rain developing after 11 a.m. Friday night conditions will deteriorate further, with showers likely and a possible thunderstorm before 11 p.m., followed by rain continuing after that time. Overnight lows will drop to around 49 degrees. Saturday will bring more showers and the possibility of another thunderstorm after 11 a.m., with highs near 61 degrees.

Weekend Outlook and Seasonal Context

Some relief will arrive Sunday, when mostly sunny skies return and temperatures rebound to near 67 degrees. However, conditions will remain cool through the overnight hours. The trend toward slightly wetter than normal conditions and near-normal temperatures is expected to continue across western Washington, though central and eastern Washington may experience above-average warmth.

Looking ahead to the broader seasonal picture, forecasters have assigned a roughly 50 to 60 percent probability that temperatures will remain above average through the summer and fall seasons. However, experts caution that such probability maps indicate forecaster confidence levels rather than specific temperature predictions, making warmer conditions likely but not guaranteed.