December in Gresham averages a daily high of 7.7°C with nights around 2.7°C. Expect roughly 18.7 wet days totalling 147.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Gresham is June–September.
Based on PORTLAND TROUTDALE AIRPORT, OR US (6.1km), 1995–2024. 27 years of December data.