September in Marysville averages a daily high of 21.4°C with nights around 9.9°C. Expect roughly 10.4 wet days totalling 50.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Marysville is July–August.
Based on EVERETT, WA US (8.6km), 1995–2024. 25 years of September data.