May in Richland averages a daily high of 23.1°C with nights around 9.2°C. Expect roughly 7.2 wet days totalling 15mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Richland is May–June.
Based on RICHLAND, WA US (3.3km), 1995–2024. 30 years of May data.