In September, Olympia typically sees daytime highs of 21.7°C and overnight lows around 8.9°C. Compared to the annual average high of 15.7°C, September runs +6.0°C.
September in Olympia averages a daytime high of 21.7°C and an overnight low of 8.9°C.
September runs +6.0°C compared to Olympia's annual average high of 15.7°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 21.7°C and cooler evenings around 8.9°C.