Arizona Weather In December 2025. In december in phoenix (arizona), the days on average last 09:56. Is december a good time to visit arizona?
Generally, you can expect in december an average temperature of 66°f / 19°c during the day and an average of 35°f / 2°c during the night. Phoenix experiences relatively mild temperatures in january, making it a popular winter escape for those seeking relief from colder climates.