Historical weather data, all-time temperature records, and monthly climate averages for SeaTac, WA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th sits right in the middle of Seattle's soggy spring, with a coin-flip chance of rain (49%) and average temps of 40–56°. The date's range tells an interesting story: back in 1966, someone was enjoying a 75° April stunner, while 1948 brought a teeth-chattering low of 31°.
SeaTac's weather history has some genuinely wild bookends — from a record-shattering 108° during the 2021 heat dome to a bone-chilling 0° in January 1950. That 108-degree day wasn't just a record, it was a civilization-testing event for a city built around mild, drizzly comfort.
Seattle is firmly a summer destination for warm-weather seekers, with highs peaking around 76–77° in mid-July and a cool, damp floor of 44° in early January. If you're trying to dodge rain, aim for July or August — the wettest stretch runs late November, when a typical week can dump over 1.6 inches.