You’re thinking about palm trees and Santa hats. Maybe a surfboard with a giant bow on it. It’s a classic vibe, but if you step off the plane at LAX in flip-flops and a tank top, you might be in for a rude awakening.
December Los Angeles weather isn't exactly the frozen tundra, but it’s definitely not the endless summer people see on Baywatch reruns. It is a month of wild contradictions. One day you’re sweating in 80-degree heat because of the Santa Ana winds, and the next, you're huddled under a puffer jacket in Santa Monica because the damp ocean breeze feels like it’s cutting right through your bones.
Honestly, the "winter" here is more of a suggestion than a season. But for a traveler or a new transplant, that suggestion can be pretty confusing.
The Temperature Rollercoaster: Why Layers Aren't Optional
If you look at the averages, everything seems fine. The National Weather Service usually pegs the average high around 66°F to 68°F and the low around 48°F. That sounds like a dream to someone coming from Chicago or New York.
But averages are liars.
In reality, a typical December day in LA feels like three different seasons packed into 24 hours.
- 6:00 AM: It’s 45 degrees. You can see your breath. You need a real coat.
- 1:00 PM: The sun is beating down. It hits 72 degrees. You’re regretting the sweater. You’re basically in a t-shirt.
- 5:00 PM: The sun drops behind the Santa Monica Mountains. The temperature plummets 15 degrees in what feels like five minutes.
This isn't just "cool." It’s a dry, biting chill that catches you off guard because you spent the afternoon getting a sunburn at The Grove.
The Coast vs. The Valley
There is a massive geographical divide you have to understand. In December, the "Marine Layer"—that thick blanket of fog—often hangs out by the beach. If you’re staying in Santa Monica or Venice, expect it to be 5 to 10 degrees cooler than if you were in Burbank or Pasadena.
Inland areas like the San Fernando Valley can actually get surprisingly "cold." It’s not rare to see frost on windshields in Northridge or Woodland Hills during a late December cold snap. Meanwhile, downtown LA might stay just warm enough to avoid it.
Rain: The "Winter" Wildcard
LA gets about 2.3 inches of rain in December on average. That doesn't sound like much, but here’s the thing: when it rains in LA, the city basically forgets how to function.
Most of the year is bone-dry. Then December hits, and we get these "Atmospheric Rivers." Instead of a light drizzle that lasts all week, we get a firehose of water for 48 hours.
- Flash Floods: Because the ground is so hard and dry most of the year, it doesn't absorb water well. Roads turn into rivers quickly.
- The Driving Factor: Locals aren't "bad" at driving in rain; they just haven't done it in eight months. The oil on the roads rises to the surface, making the 405 freeway a literal ice rink.
- The Payoff: If you catch a storm, the day after is the best weather you will ever see. The rain scrubs the smog out of the air. The San Gabriel Mountains suddenly appear, capped with snow, and the visibility is so clear you feel like you can touch the Hollywood sign from twenty miles away.
The Santa Ana Winds: The Hot December Surprise
Sometimes, the "Great Basin" over Nevada and Utah gets high pressure and pushes air toward the coast. As that air drops in elevation, it compresses and heats up.
This is the Santa Ana wind phenomenon.
It’s weird. You’ll be walking around on December 15th, and it’s 85°F and 10% humidity. The wind is howling at 40 mph. Your skin feels like parchment paper, and your hair has enough static electricity to power a small village.
For tourists, it’s a "beach day" miracle. For locals, it’s fire season anxiety. These winds are what drive the late-season wildfires you see on the news. If the winds are blowing, leave the hairspray at home and buy some heavy-duty lip balm.
What You Should Actually Pack (The Insider List)
Forget the "winter gear" you use in the Midwest. You don't need a parka. You need strategy.
- The "Shell" Jacket: A light windbreaker or denim jacket isn't enough for the evenings. Bring a medium-weight jacket or a light down "puffy" that can be compressed into a bag.
- Hoodies are the Uniform: There is a reason everyone in LA wears hoodies. They are the perfect mid-layer for when the sun goes behind a cloud.
- Sunglasses: The December sun is lower in the sky and can be incredibly blinding while driving. It's sunnier here in December than most places are in July.
- The "Just in Case" Umbrella: You probably won't use it. But if an Atmospheric River hits and you don't have one, you'll be paying $30 for a flimsy one at a CVS.
Real-World Scenarios: December Activities
The December Los Angeles weather actually makes it one of the best times for specific activities that are miserable in the summer.
Hiking
In July, hiking Runyon Canyon or Griffith Park is a death march. It’s 95 degrees and there's no shade. In December? It’s perfect. You can hike at noon, stay cool, and actually enjoy the view of the Pacific Ocean without the summer haze.
The Theme Parks
Universal Studios and Disneyland are legendary in December. Yes, the crowds are heavy near Christmas, but the weather is manageable. You aren't melting in a 90-minute line for Jurassic World. Just be ready for the temperature drop the moment the sun sets over the castle.
Whale Watching
December marks the start of the Gray Whale migration. The water is choppy and the air on the boat will be freezing—seriously, it feels 20 degrees colder on the water—but the clarity of the winter air makes spotting spouts much easier.
Actionable Tips for Your December Trip
- Check the "Dew Point," not just the Temp: If the humidity is high, 50 degrees will feel like 35. If it’s a Santa Ana day (low humidity), 50 will feel quite pleasant.
- Sunset is early: By mid-December, the sun sets around 4:45 PM. Plan your outdoor photos accordingly. The "Golden Hour" starts around 3:45 PM.
- Book the heated patio: If you’re dining out, ask for a table near a heat lamp. Even the fanciest spots in Beverly Hills rely on those "Space Age" tall heaters to keep people comfortable outdoors.
- Monitor the NWS Los Angeles Twitter/X account: They are the most accurate source for sudden wind alerts or rain intensities that generic weather apps often miss.
Basically, Los Angeles in December is a gamble, but the odds are in your favor. You’ll likely get crisp, blue-sky days that make you want to move here. Just bring a sweater for when the sun pulls its nightly disappearing act.