December in Tempe averages a daily high of 20.9°C with nights around 4.4°C. Expect roughly 3.8 wet days totalling 19.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Tempe is November–March.
Based on TEMPE ASU, AZ US (1.7km), 1995–2024. 23 years of December data.