What to Expect from Southern California’s Weather This December

December in Southern California is a magical time of year. With cooler temperatures, occasional rain showers, and an abundance of festive events, it’s the perfect month to experience everything this sunny region has to offer. Whether you're planning a winter getaway or are a local looking to enjoy the season, here's what you can expect from the weather in Southern California this December.

1. Coastal Areas: Mild and Pleasant
Southern California's coastline is famous for its moderate, year-round climate, and December is no exception. Along cities like Los Angeles, Santa Monica, and San Diego, daytime temperatures generally range from 60°F to 70°F (16°C - 21°C).

Daytime: Expect cool, crisp mornings followed by sunny afternoons. While it’s too chilly for swimming, it’s still a great time to enjoy beach walks, hiking, or visiting local attractions. December also marks the beginning of whale-watching season, especially along the coast of Malibu and Dana Point, where you may catch a glimpse of migrating gray whales.
Evenings: Nights cool off, often dipping to around 50°F (10°C). It's a perfect time to enjoy cozy evenings by a fire pit or to stroll along the piers in Santa Monica and Huntington Beach.

2. Inland Areas: Cooler Temperatures with Occasional Rain
Inland cities like Riverside, San Bernardino, and the Inland Empire experience slightly cooler temperatures in December. Average highs hover between 60°F and 70°F (15°C - 21°C), while overnight lows can drop into the 40s°F (5°C - 9°C).

Daytime: The days are generally sunny with the occasional cloud cover, especially after a rainstorm. December brings a slight chance of rain to the Inland Empire, but it’s not likely to be heavy or long-lasting. This is also a great time for hiking in local parks like Joshua Tree National Park or the Santa Monica Mountains, where the weather is cool enough to enjoy the outdoors comfortably.
Evenings: Evening temperatures can drop significantly, and frost is possible in more rural or elevated areas. Make sure to pack a jacket or sweater for outdoor activities after sunset.

3. Desert Regions: Chilly Mornings and Pleasant Afternoons
The desert regions of Southern California, including Palm Springs, Joshua Tree, and the Coachella Valley, experience much cooler temperatures in December compared to the scorching summer months. Daytime temperatures typically range from 60°F to 70°F (15°C - 21°C), while the desert nights can get cold, with lows dipping into the 40s°F (4°C - 9°C).

Daytime: Expect sunny, crisp days perfect for exploring the desert landscape. Outdoor activities such as hiking, sightseeing, and exploring local parks are best done during the afternoon when the temperatures are mild. Desert wildflowers may start to bloom in certain areas, offering a unique visual treat during the cooler months.
Evenings: Nights in the desert can be chilly, often falling to 40°F or lower, so be prepared for the temperature drop once the sun sets. Desert stargazing can be spectacular this time of year, with clear skies and minimal light pollution.

4. Mountain Areas: Snow and Cold Weather
December marks the beginning of the ski season in Southern California’s mountain regions, such as Big Bear Lake and Lake Arrowhead. These areas are typically cold, with temperatures ranging from 30°F to 50°F (1°C - 10°C) during the day.

Daytime: While it’s cold, daytime temperatures are often manageable, and snowfall is common during December, especially at higher elevations. If you're a fan of winter sports, this is the best time to visit the mountains for skiing, snowboarding, or even just enjoying the winter scenery.
Evenings: Expect cold nights, often dipping well below freezing in mountain towns. It’s the perfect time to enjoy a warm beverage by the fireplace after a day of skiing or snowshoeing.

Rain and Holiday Season
While December typically brings cooler weather, it is also the season for occasional rain showers, especially along the coast and in the Inland Empire. The chance of significant rainfall is higher in December than in other months, but storms tend to be brief. If you're visiting Southern California during the holidays, don’t let a little rain spoil your plans — it’s usually light and followed by clear skies.
Southern California also comes alive with holiday spirit in December, offering festive events, outdoor holiday markets, and Christmas light displays. Whether you’re experiencing the holiday season in Los Angeles, exploring Disneyland, or checking out the holiday lights in San Diego, the cooler weather makes outdoor activities more enjoyable.

Key Takeaways:

Coastal Areas: Mild days (60°F - 70°F) with cooler evenings (around 50°F).
Inland Areas: Daytime highs in the 60s°F to low 70s°F, with cooler evenings in the 40s°F.
Desert Regions: Pleasant daytime temperatures (60°F - 70°F), with chilly nights in the 40s°F.
Mountain Areas: Cold temperatures with snow likely, especially at higher elevations.
Rain: Occasional rain showers, particularly along the coast and inland.

Southern California weather in December offers a refreshing break from the heat of summer, making it the perfect time to explore the region's diverse landscapes. From mild coastal temperatures to snowy mountain retreats, there's something for everyone this holiday season. Whether you're planning to relax by the beach, hike in the desert, or hit the slopes, Southern California offers a comfortable and festive setting for all your December adventures.
This December weather blog provides an overview of what visitors and locals can expect in Southern California during the holiday season. Let me know if you'd like to add or adjust any details!