When you escape to the Valley of the Sun for the winter holidays, you're trading snow shovels for short sleeves during the afternoon. Phoenix December weather brings mild, comfortable days and genuinely crisp desert evenings, making it one of the absolute best times of the year to explore outdoor attractions. According to the National Weather Service Phoenix, normal daytime highs hover around 65 to 67 degrees Fahrenheit, while overnight lows dip into the mid-40s.
You won't find scorching triple-digit heat, but you also won't find freezing arctic blasts. Instead, this month offers a reliable desert climate that feels like perpetual spring. If you're planning a trip or considering a move, understanding daily temperature shifts, packing requirements, and local seasonal patterns will help you make the most of your time in central Arizona.
Average Temperatures Breakdown
To pack correctly and set realistic expectations, look closely at how the thermometer behaves throughout a typical December day in Maricopa County. The desert environment creates wide temperature swings between sunup and sundown.
Daytime Highs and Afternoon Warmth
By early afternoon, average high temperatures reach roughly 67 degrees Fahrenheit. On many afternoons, clear skies and strong winter sunshine push the ambient air temperature past 70 degrees. If you're hiking Camelback Mountain or walking through the Desert Botanical Garden, you'll likely shed your jacket and work up a sweat.
Nighttime Lows and Desert Chill
The moment the sun dips behind the horizon, the lack of humidity causes heat to radiate rapidly back into the atmosphere. Nighttime lows drop down to an average of 44 degrees Fahrenheit. While freezing temperatures in the urban core are rare, outer valley areas and rural stretches can experience near-frost conditions on clear, still nights.
Humidity and Precipitation
December is generally a dry month, though it is slightly wetter than the arid summer months. Total monthly rainfall typically stays under an inch, averaging around 0.8 inches across a handful of damp days. Relative humidity stays comfortable, usually hovering between 40% and 50% during the cooler morning hours before drying out in the afternoon.
What to Wear: The Layering Strategy
Packing for Phoenix in December requires a wardrobe that adapts to a 25-degree daily temperature swing. If you step outside at 7:00 AM for a morning run, you'll want long sleeves and a beanie. By 2:00 PM, you'll be rolling up your sleeves.
- Base Layers: Pack breathable t-shirts and light shirts for the warm afternoons.
- Insulation: Bring lightweight sweaters, cardigans, or hoodies for mornings and evenings.
- Outerwear: A proper jacket, fleece, or wool coat is essential for night outings, outdoor dining, and stargazing.
- Footwear: Closed-toe walking shoes or hiking boots are ideal for rugged desert trails and urban explorations.
Outdoor Activities and Recreation
Because the oppressive summer heat is long gone, December is the peak season for outdoor recreation in Arizona. Local parks and wilderness areas experience their highest visitor volumes during this month.
- Hiking and Trail Running: Trails across Papago Park, South Mountain, and the McDowell Sonoran Preserve offer comfortable conditions all day long.
- Golfing: The region's premier golf courses hit peak form with overseeded turf, though morning tee times require a windbreaker until the sun clears the mountains.
- Festivals and Holiday Lights: Events like Las Noches de las Luminarias at the Desert Botanical Garden draw large crowds who comfortably walk outdoor paths after dark.
Common Mistakes Travelers Make
Visitors often make a few predictable errors when planning a December trip to the desert southwest. Avoiding these missteps ensures a much smoother vacation.
- Underestimating Nighttime Cold: Assuming that "Arizona in winter" means warm weather 24/7 leaves many tourists shivering outside restaurants after sunset. Always bring a coat for the evening.
- Skipping Sun Protection: Even though it's cold in the morning, the winter sun in Arizona remains intense. High UV indexes still require sunscreen and sunglasses during midday outdoor activities.
- Forgetting Pool Heating: Many hotels and rental properties have outdoor pools, but unless a property explicitly features a heated pool, the water will be far too cold for comfortable swimming in December.
Frequently Asked Questions
Does it ever snow in Phoenix in December?
Snow in the actual city of Phoenix is extraordinarily rare. While surrounding high-elevation towns like Flagstaff receive heavy winter snowpacks, Phoenix valley floors experience snow only under anomalous meteorological conditions. The last recorded trace amounts of snow in the city occurred decades ago.
Can you swim in outdoor pools in December?
Unheated hotel pools are typically too cold for swimming, as water temperatures drop into the 50s. However, many resorts maintain heated pools specifically for winter guests, so it's best to verify amenities directly with your lodging provider before booking.
Are desert trails crowded in December?
Yes. Because December offers the ideal window for outdoor recreation before spring training baseball and summer heat arrive, popular trailheads fill up very early in the morning. Arriving by sunrise is the best way to secure parking at major state and regional parks.
How short are the daylight hours?
December hosts the winter solstice, meaning days are at their shortest. Sunrise occurs around 7:30 AM, and sunset happens fairly early, right around 5:30 PM. Plan your outdoor adventures with this compressed daylight window in mind.
