The Office of the Washington State Climatologist has just released their September, 2017 report which includes the August, 2017 climate summary, drought and streamflow update, and temperature and precipitation outlook as well as some information about the brief meteorological impact the solar eclipse had on our region.
Quick synopsis: Average August temperatures were warmer than normal throughout the entire state of Washington. SeaTac temperatures averaged 4.2 degrees F higher than normal for the month. Precipitation was minimal and below normal, but rainfall usually is minimal for the month of August anyways. The seasonal outlook for September suggests continued above average temperatures throughout much of the state with below normal precipitation. The longer-term September through November outlook continues to call for above normal temperatures with variable precipitation.