September in Pasco averages a daily high of 27°C with nights around 12.3°C. Rain is rare — about 2.8 wet days and 7mm across the month. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Pasco is May–June.
Based on KENNEWICK, WA US (3.2km), 1995–2024. 30 years of September data.