December temperatures in Phoenix offer a welcome escape from freezing winters elsewhere, bringing pleasant afternoon highs around 66°F to 67°F (19°C) and crisp desert nights dropping to a chilly 43°F to 45°F (6°C to 7°C). While it's the coolest month of the year for the city, visitors and residents rarely see extreme cold, making it prime time for outdoor exploration, hiking, and holiday events.
Understanding how the desert climate shifts from warm sunlit afternoons to brisk evenings helps you pack right and plan daily activities without surprises. This guide breaks down exact averages, clothing strategies, and common misconceptions about winter in the Valley of the Sun.
Daytime Warmth and Sunshine
Days in December are bright and clear, averaging nearly eight hours of sunshine daily. Afternoons peak around 2:00 PM, hitting comfortable levels where a light jacket or long sleeves feel ideal.
- Average afternoon highs: 66°F to 67°F
- Sunny days: Roughly 15 completely clear days
- Rainfall: Minimal, averaging around 0.7 to 1.0 inches for the entire month across about four damp days
Because humidity stays low, the air feels crisp rather than damp. You won't need heavy winter coats during peak daylight hours, making outdoor dining or walking through the Desert Botanical Garden very comfortable.
The Nighttime Drop
The desert loses heat quickly once the sun sets around 5:30 PM. Within a couple of hours, temperatures slide down from the comfortable sixties into the forties.
- Average overnight lows: 43°F to 45°F
- Freezing nights: True freezes happen rarely, averaging about once a decade in urban Phoenix.
If you're heading out to evening holiday light displays or sitting around an outdoor patio fire pit, you'll definitely want a heavy sweater, fleece, or wool coat.
What to Pack for December in Phoenix
Packing for a winter trip to Phoenix requires layers because of the rapid temperature swings between 2:00 PM and 8:00 PM.
- Light layers for day: T-shirts, long-sleeve cotton shirts, and light cardigans or denim jackets.
- Warm layers for night: Heavy sweaters, fleece jackets, scarves, and closed-toe shoes.
- Sun protection: Sunglasses and sunscreen remain essential even in winter due to high solar angle on clear days.
- Hiking gear: Sturdy boots and moisture-wicking layers if you plan to hit trails like Camelback Mountain or Piestewa Peak.
According to the National Weather Service, winter weather patterns across the Southwest remain generally stable, though occasional Pacific storms can bring light mountain snow to northern Arizona while Phoenix gets brief showers.
Common Mistakes to Avoid
Visitors often make a few predictable errors when planning a December trip to Arizona.
- Underestimating nighttime cold: Packing only warm-weather resort wear leaves tourists shivering once the sun goes down. Always bring winter evening wear.
- Assuming resort pools are heated: Unless you check with your hotel beforehand, outdoor pools can feel too cold for swimming during December.
- Skipping hydration: Because the air is dry and cool, people often forget to drink enough water while hiking or walking outdoors.
You can check official regional tourism updates and events through Visit Phoenix to find local winter festivals, marathons, and holiday markets.
Frequently Asked Questions
Does it ever snow in Phoenix in December?
No, measurable snow in the city of Phoenix proper is virtually nonexistent in December due to warm daytime ground temperatures.
Can you swim in Phoenix hotel pools in December?
Only if the pool is actively heated. Unheated water temperatures drop significantly during winter, making swimming uncomfortable for most people.
Is December a busy month for tourism in Phoenix?
Yes, tourism picks up significantly around the mid-December holiday weeks as visitors flock south to escape colder climates elsewhere in the country.
How short are the days in December?
December hosts the winter solstice, giving Phoenix about 9 hours and 56 minutes of daylight, with sunsets occurring just before 5:30 PM.
