It is a total myth. You see it on TV every year during the Rose Parade—blue skies, palm trees, and people in t-shirts. Everyone thinks Los Angeles weather dec is just a slightly breezier version of July. They pack a suitcase full of shorts and flip-flops, step off the plane at LAX, and immediately freeze.
Winter in LA is weird. It’s inconsistent.
One day you’re sweating in 80-degree heat because the Santa Ana winds are screaming off the desert, and the next, you’re huddled under a heat lamp at an outdoor bar in West Hollywood because the temperature plummeted thirty degrees the second the sun went down. If you want to survive December in Southern California without buying a $60 tourist sweatshirt you’ll never wear again, you have to understand the microclimates.
The Highs, the Lows, and the Santa Ana Wildcard
Statistically, December is one of the coolest months in the Los Angeles basin. But "cool" is relative. The National Weather Service records usually show average highs sitting around $68^{\circ}F$ ($20^{\circ}C$), with lows dipping down to $48^{\circ}F$ ($9^{\circ}C$).
That sounds mild. It isn’t.
Because the air is so dry, the "real feel" changes the moment you move into the shade. You can literally walk across the street and feel like you’ve switched seasons.
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Then there are the Santa Ana winds. These are those hot, dusty gusts that blow in from the Great Basin. When they hit, Los Angeles weather dec can spike into the high 80s. It feels apocalyptic. The air gets electric, your skin dries out instantly, and the fire risk skyrockets. It’s a bizarre sensation to see Christmas lights draped over cacti while it's 85 degrees at 2:00 PM.
Most people don't realize that December is also the start of the rainy season. While LA isn't Seattle, when it rains here, it pours. We get these "Atmospheric Rivers"—basically massive conveyor belts of moisture from the Pacific. If one of those hits during your trip, the 405 freeway becomes a parking lot and the city basically forgets how to function.
Why the Beach is a Trap in December
If you’re planning to stay in Santa Monica or Venice, double your layers. The marine layer—that thick, salty fog—is a constant player in the Los Angeles weather dec drama.
Even if it’s a beautiful, sunny day in Pasadena or Northridge, the coast can stay shrouded in "June Gloom’s" winter cousin. The ocean temperature is around $58^{\circ}F$. That giant body of cold water acts like a refrigerator. While inland valleys are soaking up the sun, the beach can be a damp, 55-degree mess.
Honest advice? Don't plan on swimming unless you have a thick 4/3mm wetsuit. The water is brutal this time of year. Surfers love it because the winter swells are world-class, but for a casual dip? Forget about it. You'll see tourists trying to brave the waves at Malibu; they usually last about three minutes before running for a towel.
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The Sunset Shiver
This is the most important thing to know about Los Angeles weather dec. The sun sets early—usually around 4:45 PM.
The temperature drop is violent.
In a matter of twenty minutes, the city goes from "perfect light jacket weather" to "I need a parka." This is due to the lack of humidity. There’s nothing in the air to hold the heat once the sun vanishes behind the Santa Monica mountains. If you’re heading to an outdoor event like the LA Zoo Lights or Enchanted Forest of Light at Descanso Gardens, you need real winter gear. I’m talking gloves and a beanie. People laugh until they’re standing in a canyon at 8:00 PM and it’s $42^{\circ}F$.
Rainfall Realities and the "Storm Watch" Hysteria
Los Angeles averages about 2.4 inches of rain in December. That doesn't sound like much, but it usually falls all at once.
Local news stations go into "Storm Watch" mode the second a cloud appears. It’s a bit of a running joke, but for travelers, it’s a headache. The infrastructure in LA isn't great for drainage. Potholes appear out of nowhere. Mudslides can shut down parts of Pacific Coast Highway.
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If you see rain in the forecast for your December trip:
- Expect traffic to triple. A 20-minute Uber becomes a 90-minute ordeal.
- Check the mountains. December is when the San Gabriel Mountains start getting their first real snow. You can be at the beach in the morning and skiing at Mt. Baldy or Big Bear by the afternoon.
- Watch the canyons. If you're hiking in places like Runyon or Griffith Park after a rain, the trails are basically slick clay. You will ruin your white sneakers.
How to Pack (The Expert Version)
Forget the "California Style" you see on Instagram. Real locals dress like onions.
You need a base layer that can handle heat. A t-shirt or a light linen shirt is fine. Over that, you need a medium-weight sweater or a "shacket." Finally, you need a wind-resistant outer shell or a denim jacket.
Don't bother with an umbrella. The wind usually turns them inside out anyway. Get a raincoat with a hood.
Also, consider your footwear. Los Angeles is a walking city in small bursts, but the pavement gets cold. Flip-flops are for the hotel pool only. Socks and closed-toe shoes are your best friends once the Los Angeles weather dec patterns shift in the evening.
Surprising December Perks
Despite the weirdness, December is actually one of the best times to visit if you hate the smog. The winter rains scrub the atmosphere clean. On the day after a storm, the visibility is insane. You can stand on the Griffith Observatory terrace and see all the way to Catalina Island. The air smells like sage and eucalyptus instead of exhaust.
The lighting is different too. The sun sits lower in the sky, creating a "Golden Hour" that lasts for most of the afternoon. It’s a photographer’s dream. The shadows are long, the colors are deep, and the sunsets are often pink and purple explosions thanks to the high-altitude ice crystals.
Actionable Steps for Your Visit
- Monitor the "Dew Point": Check the humidity levels on your weather app. If it’s below 15%, expect Santa Ana conditions. Hydrate twice as much as usual and buy a heavy-duty lip balm.
- Book Mid-City Stays: To avoid the extreme cold of the coast or the extreme heat of the valleys, stay somewhere like West Hollywood or Silver Lake. They tend to stay more temperate.
- The "4 PM Rule": Whatever you are doing, return to your car or hotel at 4:00 PM to grab your heavy coat. Do not assume you'll be fine in your light sweater. You won't be.
- Download a "Radar" App: Don't just trust the "percentage chance of rain." Look at the live radar. LA rain often moves in narrow bands; it might be pouring in Santa Monica while it's bone-dry in Downtown.
- Check Canyon Closures: If you're planning a scenic drive through Malibu Canyons or Topanga, check the LA County Public Works site first. Rockfalls are common in December after the first big rain.