You’ve seen the movies. Everyone is in shorts, sipping a cocktail by a sparkling pool while the desert sun blazes. But honestly? If you’re looking at a las vegas 21 day forecast for the second half of January and early February, that "desert heat" is basically a myth.
Right now, it’s actually kinda chilly.
Most people pack for the Vegas they see on TV, not the one that actually exists in the winter. If you stepped outside last night, you felt that 48°F air with a 1 mph breeze coming off the west. It’s crisp. It’s dry. And if you aren't prepared for the wild temperature swings, you’re going to spend your vacation buying a $85 souvenir hoodie just to survive the walk between Caesars and the Bellagio.
The Reality of the Las Vegas 21 Day Forecast
Let’s look at the numbers because they don't lie, even if the bright sunshine feels deceptive. For today, Sunday, January 18, 2026, we’re topping out at 65°F. That sounds decent, right? But the low is 43°F. That’s a 22-degree drop the moment the sun slips behind the Spring Mountains.
The upcoming week stays fairly consistent. Monday, January 19, sees a high of 69°F and a low of 43°F. Tuesday drops a bit to a 65°F high and a much colder 39°F low. Wednesday through Friday (January 21–23) holds steady with highs around 65°F or 66°F and lows hovering between 39°F and 44°F.
If you’re planning out the full las vegas 21 day forecast, you need to understand the "ridge" factor. Currently, the National Weather Service has been tracking a high-amplitude ridge over the Pacific Coast. This is keeping things dry and technically "warmer than normal" for January. Without this ridge, we’d likely be seeing highs in the 50s. By the time we hit late January and move into the first week of February, that ridge starts de-amplifying.
What does that mean for your trip?
Basically, the "bonus" warmth we’re having now might fade. History tells us that late January is often the coldest stretch for the valley. While the forecast through January 27 shows us hitting 70°F again, don't get used to it. The transition to February often brings "chilly" periods, as noted by long-range outlooks from sources like the Farmers' Almanac and local meteorologists.
Breaking Down the Next Two Weeks
- Today (Jan 18): Mostly cloudy, high of 65°F.
- The MLK Holiday (Jan 19): Sunny, 69°F. Great for a hike, but watch the 6 mph north wind.
- The Mid-Week Dip: Lows hit 39°F on Tuesday and Wednesday nights. This is "see your breath" weather.
- The Late Jan Peak: Tuesday, Jan 27, might be the warmest day of the month, hitting 70°F.
Why the UV Index and Humidity Matter More Than You Think
Vegas is dry. Like, 24% humidity today dry. On Monday, it drops to 23%. By Thursday, we’re looking at 20%.
People forget that dry air doesn’t hold heat. It also zaps the moisture out of your skin and eyes. If you’re walking the Strip, you’ll feel fine in the sun, but the second you hit a shadow or the sun goes down, it feels ten degrees colder than the thermometer says.
Also, check the UV index. Even in January, it’s hitting a 3 on Monday and Tuesday. It’s not "burn in ten minutes" territory, but if you’re out at Red Rock Canyon all day, that desert sun will still get to you.
Survival Tips for the Vegas Winter
Honestly, the biggest mistake is the "pool" mentality. Most outdoor pools are closed. Some resorts, like Circa or the Stadium Swim at the D, keep things heated year-round, but you better have a robe ready for the walk back to the locker room.
- Layers are your best friend. A t-shirt under a light sweater with a jacket on top is the only way to handle the 65°F day to 43°F night transition.
- Lip balm and lotion. You will crack. It’s a desert.
- Check the wind. A 6 mph wind might not sound like much, but in the shadows of the massive casinos, it creates a wind-tunnel effect that makes 50°F feel like 40°F.
Looking Toward February
As we push past the 14-day mark of the current las vegas 21 day forecast, we enter the early February window. This is a weird time for the city. You’ve got the International Fireworks Championship at the Las Vegas Motor Speedway on February 21, and the massive Super Bowl Sunday crowds around February 8.
Meteorologically, February is when the "transition" starts. We start seeing a 61% chance of shifting into ENSO-neutral conditions. Translation? The weather becomes a bit more unpredictable. We might get those "rainy west" periods mentioned in long-range models. While Vegas only averages about 0.6 inches of rain in January, February can be slightly wetter.
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If you are coming for the fireworks or the big game, expect the highs to stay in the low 60s and the nights to remain cold. It’s prime "leather jacket" weather.
Actionable Strategy for Your Trip
Stop checking the "daily high" and start checking the "hourly drop." If you have dinner reservations at 7:00 PM, look at what the temperature will be when you leave the restaurant at 9:00 PM.
Trust me, that 43°F low hits a lot harder when you’re standing in a taxi line at 1:00 AM than it does when you're reading about it on a screen. Pack a real coat, keep the sunscreen handy for the morning hikes, and remember that "sunny" in the desert doesn't always mean "warm."
Plan your outdoor activities—like the Red Rock loop or the Hoover Dam—for between 11:00 AM and 3:00 PM. That’s your golden window for the best weather. Anything earlier or later, and you’re in the "deep freeze" zone.