December in Phoenix offers a welcome escape from harsh winter freezes elsewhere, delivering pleasant daytime highs averaging around 66°F (19°C) and crisp evening lows near 45°F (7°C). While it ranks as one of the coolest months of the year for the region, the desert climate remains remarkably mild, featuring abundant sunshine and low humidity. Visitors and residents experience a distinct daily temperature swing of about 20 degrees, making clear skies ideal for outdoor recreation without the intense heat of summer.
Understanding the nuances of winter weather patterns in the Valley of the Sun helps travellers pack appropriately and plan itineraries effectively. From daily climate norms to what to expect after sunset, here is a detailed breakdown of Phoenix weather in December.
Temperature Breakdown Across the Month
Early December tends to feel slightly warmer, with afternoon highs frequently reaching 68°F (20°C) during the first ten days of the month. As winter progresses toward the solstice, daily averages dip slightly, with late December seeing typical afternoon highs around 65°F (18°C) and overnight lows dropping to 44°F (7°C).
Freezing temperatures inside the city proper are rare, occurring on fewer than one night a decade. However, nearby desert expanses and suburban valleys often experience colder microclimates, dropping a few degrees lower than urban heat-island zones. More journalism by Travel + Leisure highlights similar views on the subject.
- Early December (Dec 1–10): Highs around 68°F (20°C), lows around 47°F (8°C).
- Mid December (Dec 11–20): Highs around 66°F (19°C), lows around 45°F (7°C).
- Late December (Dec 21–31): Highs around 65°F (18°C), lows around 44°F (7°C).
Sunshine, Rainfall, and Humidity
Phoenix averages roughly 77 percent of possible sunshine during December, translating to about eight hours of direct sun daily. Although December is statistically one of the cloudier months of the year for the region, completely overcast days remain the exception rather than the rule.
Precipitation is minimal, with the city recording an average monthly total of less than one inch across roughly four to five rainy days. Storm systems passing through are typically brief, leaving behind crisp, exceptionally clear air. Relative humidity hovers comfortably around 43 to 52 percent, making the crisp winter air feel refreshing rather than biting.
What to Wear and How to Layer
The key to staying comfortable in Phoenix during December is mastering the art of layering. Because the temperature drops rapidly as soon as the sun dips below the horizon, what feels warm at 2:00 PM requires a heavy jacket by 6:00 PM.
- Daytime Wear: Light sweaters, long-sleeve shirts, and comfortable denim or hiking pants work best for afternoon outings.
- Evening Wear: Bring a warm fleece, wool coat, or windbreaker for outdoor dining, evening walks, or stargazing.
- Footwear: Sturdy walking shoes or trail runners are essential for exploring desert parks and city streets.
According to the National Weather Service, winter UV levels remain moderate, but sun protection is still necessary during extended outdoor excursions, especially when reflecting off light desert sand.
Best Outdoor Activities for December Climate
The mild climate creates premier conditions for active tourism. Popular pastimes take advantage of the cool air:
- Desert Hiking: Trails on Camelback Mountain, Piestewa Peak, and the McDowell Sonoran Preserve stay comfortable all day long.
- Golfing: Dozens of championship golf courses across Scottsdale and Phoenix experience peak play conditions during this month.
- Festive Evening Events: Seasonal staples like Las Noches de las Luminarias at the Desert Botanical Garden and ZooLights draw large crowds to view holiday displays in cool evening weather.
Frequently Asked Questions
Does it ever snow in Phoenix in December?
No. Snowfall in the city proper is virtually unheard of due to low elevation and warm winter baselines. Snow is strictly confined to Arizona's high-country mountain towns like Flagstaff.
Do I need a pool heater if I visit in December?
Most standard outdoor hotel pools are unheated and will feel too chilly for comfortable swimming, as water temperatures drop into the 50s. However, many resorts maintain heated pools and hot tubs specifically for winter guests.
How windy is Phoenix in December?
December is generally the calmest month of the year in Phoenix, with average wind speeds hovering around 4 miles per hour, minimizing any windchill effect.
Are daylight hours short during this month?
Yes, December features the shortest days of the year, with sunset occurring around 5:30 PM. Plan outdoor mountain hikes earlier in the day to ensure you return safely before twilight.
