May in Corvallis averages a daily high of 20°C with nights around 6.9°C. Expect roughly 13.1 wet days totalling 58.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Corvallis is June–September.
Based on CORVALLIS STATE UNIVERSITY, OR US (9.6km), 1995–2024. 30 years of May data.