Seattle, WA Climate in September

Temperature for September

In Seattle, WA during September the average high temperature is 71.5°F. The hottest day on record was September 3, 1988 when the temperature hit 98.1°F.

Seattle, WA daily average and extreme temperature range for September

Low Temperature

During September the overnight temperature drops to an average of 51.3°F, with the lowest temperature of 33.4°F being recorded on September 19, 1985. In September it has never frozen overnight.

Precipitation for September

In September the average monthly rainfall in Seattle, WA is 1.89 inches with rain usually falling on between 10 and 11 days. 1993 was the driest September with only 0.03 inches of rain falling, and 1978 was the wettest September with 18.43 inches of rain. The wettest single day in September was 2 September 1978 when 12.13 inches of rain fell.

Tornados are reported on 0 and 1 days in September. In September there have been some years when thunderstorms have occurred, although there are other years when there hasn't been a thunderstorm in September.