December in Renton averages a daily high of 8.3°C with nights around 2.6°C. Expect roughly 17.1 wet days totalling 108.4mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Renton is July–August.
Based on RENTON MUNICIPAL AIRPORT, WA US (1.4km), 1995–2024. 27 years of December data.