In September, Federal Way typically sees daytime highs of 21.2°C and overnight lows around 10.5°C. Compared to the annual average high of 15.5°C, September runs +5.8°C.
September in Federal Way averages a daytime high of 21.2°C and an overnight low of 10.5°C.
September runs +5.8°C compared to Federal Way's annual average high of 15.5°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 21.2°C and cooler evenings around 10.5°C.