September in Burien averages a daily high of 21.5°C with nights around 11.9°C. Expect roughly 8.8 wet days totalling 44.2mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Burien is July–August.
Based on SEATTLE TACOMA AIRPORT, WA US (3.8km), 1995–2024. 30 years of September data.