December in Richland averages a daily high of 4.2°C with nights around -2.2°C. Expect roughly 12.7 wet days totalling 30.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Richland is May–June.
Based on RICHLAND, WA US (3.3km), 1995–2024. 30 years of December data.