September in Yakima averages a daily high of 26.2°C with nights around 7.4°C. Expect roughly 3.3 wet days totalling 6.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Yakima is May–June.
Based on YAKIMA AIRPORT, WA US (4.8km), 1995–2024. 30 years of September data.