You’re standing on the Strip, looking at a wall of black clouds over Red Rock Canyon, and your phone says it’s 0% chance of rain. It’s frustrating. Las Vegas weather radar is a finicky beast because the Mojave Desert plays by its own rules. Most people think a radar is just a giant X-ray for the sky that tells you exactly when to move the pool party indoors, but in Southern Nevada, the geography actually fights the technology.
It’s weird.
The National Weather Service (NWS) operates the primary radar for the region, known technically as KEPX. It sits way out in Searchlight, Nevada, about 60 miles south of the city. Because the Earth is curved—shocking, I know—that radar beam is already thousands of feet in the air by the time it reaches the Las Vegas Valley. If a storm is "shallow," the radar might overshoot it entirely. You see a clear screen, but you’re getting soaked.
Understanding the KEPX Blind Spots
Living here, you learn that the mountains are basically "radar shields." The Spring Mountains to the west and the Sheep Range to the north create what meteorologists call beam blockage.
When a monsoon cell creeps up from Arizona or the Gulf of California, the las vegas weather radar has a relatively clear shot. But if a winter system rolls in from the Pacific, those 11,000-foot peaks at Mount Charleston can chop the radar signal to pieces. This is why you’ll often see "ghost" storms or weird gaps in the coverage. It’s not that the rain isn't there; it’s that the beam can't see through the rock.
The NWS Las Vegas office at 7851 S. Dean Martin Dr. spends a lot of time "ground truthing." This is a fancy way of saying they check Twitter (X) and webcams to see if what the radar says is actually happening. If you're relying on a generic weather app, you're getting a smoothed-out, often delayed version of the KEPX feed. For real accuracy, you have to look at the "Base Reflectivity" versus "Composite Reflectivity." Base shows you the lowest tilt of the radar. Composite shows the maximum intensity found in any elevation. In Vegas, you want the Base. If the Composite looks scary but the Base is empty, the rain is likely evaporating before it hits your head.
Virga: The Great Desert Tease
Have you ever seen those long, grey streaks hanging from clouds that never quite touch the ground? That’s virga.
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On a las vegas weather radar screen, virga looks like a massive rainstorm. It shows up as deep greens and even yellows. You run to the garage to close the windows, but nothing happens. The air in the Mojave is so incredibly dry—often with humidity below 10%—that the raindrops literally vanish into thin air as they fall.
This creates a dangerous phenomenon called a dry microburst. The evaporating rain cools the air rapidly, making it dense and heavy. That air then crashes toward the ground like a lead weight. Even if the radar doesn't show "precipitation," it might be showing "velocity," which tracks the wind speed within those disappearing clouds. In 2023, we saw winds over 70 mph from these "invisible" storms. If you see a bright red or green "couplet" on a velocity map near Harry Reid International Airport, stay inside, even if the pavement is bone dry.
The Problem With "Future Radar"
Most apps have a "Future Cast" feature. Honestly? It’s mostly guesswork in the desert. Because our storms are often convective—meaning they pop up locally due to heat rather than moving in a long line from California—the computer models struggle. A storm can go from non-existent to a flash flood warning in about 15 minutes.
If you’re checking the las vegas weather radar during monsoon season (June to September), don’t look at the forecast three hours out. Look at the "Loop" for the last 30 minutes. Is the cell growing? Is it moving toward the valley floor? The concrete of the Strip creates an "urban heat island" effect that can actually split storms or intensify them as they cross over the hot asphalt.
Flash Floods and the Radar Reality
Las Vegas is basically a giant funnel. When the radar shows "training"—where storms follow each other like rail cars over the same spot—you have a problem.
The Regional Flood Control District has its own network of rain gauges that are way more useful than radar when things get hairy. They have a map called the "Flood Threat Vector." It combines the NWS radar data with physical sensors in the washes. Even if the las vegas weather radar looks like the storm is "light," if three inches of rain fell in the mountains 20 minutes ago, that water is headed for the LINQ parking garage or the Flamingo Wash.
The radar doesn't "see" the water on the ground. It only sees it in the air.
How to Read the Colors Like a Local
- Light Green: Usually just high-level moisture or virga. You won't get wet.
- Dark Green: Actual rain. Finally.
- Yellow/Orange: This is where the hail lives. In Vegas, hail is usually small but can be intense.
- Red/Pink: This is a heavy core. If this stays over one neighborhood for more than 10 minutes, the street corners will flood.
- Blue/White: Often signifies "anomalous propagation." Basically, the radar beam hit a temperature inversion or a mountain and got confused. If the sky is clear but the radar is white, it's a glitch.
The Dual-Pol Upgrade
Back in 2012, the KEPX radar got a "Dual-Pol" (Dual Polarization) upgrade. Before this, the radar only sent out horizontal pulses. Now, it sends both horizontal and vertical.
This matters for Vegas because it helps the NWS distinguish between rain, hail, and "non-weather" targets. We have a lot of dust here. Sometimes, a big dust devil or a "haboob" (a wall of dust) will show up on the las vegas weather radar. With Dual-Pol, meteorologists can look at a metric called the "Correlation Coefficient." If that number drops, it means the objects in the air aren't uniform. Usually, that means it's debris or dust, not rain. If you’re seeing a "debris ball" on radar during a high-wind event, that’s actually roofing material or desert sand, not a thunderstorm.
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Why You Should Use the NWS Site Directly
Third-party apps like WeatherBug or The Weather Channel are fine for a general vibe. However, they often lag. During a severe weather warning, that 5-minute delay is the difference between getting your car under a carport and having it dented by hail.
The National Weather Service’s mobile site (mobile.weather.gov) is ugly. It looks like it was designed in 1998. But it’s the raw data. It doesn't have the "smoothing" algorithms that make the las vegas weather radar look prettier but less accurate. You want the raw pixels. You want to see the "hook" echoes if they exist, though tornadoes are incredibly rare here. We do get them, though—usually "landspouts" that are weak but can still flip a shed.
High-Resolution Rapid Refresh (HRRR)
When I want to know what’s actually going to happen in Summerlin versus Henderson, I look at the HRRR model data. This isn't a radar itself, but a short-term model that updates every hour. It’s incredibly good at predicting "outflow boundaries."
An outflow boundary is like a mini-cold front that kicks out of a dying thunderstorm. On the las vegas weather radar, this looks like a very thin, faint green line moving away from a storm. Even if there is no rain on that line, it will bring 40 mph winds and a 20-degree temperature drop. If you’re out on Lake Mead, seeing that thin line on the radar is your signal to get off the water immediately. The waves will go from one foot to four feet in seconds.
Better Ways to Track Vegas Weather
Stop trusting the "Daily Forecast" icon. It's useless in the desert. Instead, follow these steps to stay ahead of the weather.
First, check the las vegas weather radar for the "Southwest Sector." Don't just look at the city. Look at what’s happening in Needles, CA, and Kingman, AZ. Storms almost always track from the southwest or south during the summer. If Kingman is getting hammered, you have about two hours.
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Second, use the "MesoWest" stations. These are private and public weather stations located all over the valley. If the radar shows rain over the Strip, but the MesoWest station at the Bellagio shows 0.00 inches of rain, you know it's virga.
Third, watch the "Skew-T" diagrams if you're a real weather nerd. These show the vertical profile of the atmosphere. If there’s a lot of "Convective Available Potential Energy" (CAPE), the radar is going to light up like a Christmas tree by 2:00 PM once the sun hits the mountains.
Practical Steps for Your Next Outing
- Ignore the percentage: A 20% chance of rain in Vegas doesn't mean it might rain. It means 20% of the area will get hit, and those areas will likely see flash flooding.
- Watch the Loop: Static radar images are deceptive. You need to see the direction of travel. Use the 30-minute loop to see if the cell is expanding (growing taller) or collapsing (dumping rain).
- Check the "Echo Tops": This shows how high the clouds are. In Vegas, if the echo tops exceed 40,000 feet, expect lightning and heavy downpours.
- Avoid the Washes: If the radar shows red over the mountains, stay out of the storm channels in the city, even if it's sunny where you are. The water travels fast.
The las vegas weather radar is an incredible tool, but it's limited by the very geography that makes the city beautiful. Between the beam blockage from the mountains and the extreme dryness of the air, what you see on the screen is often a "suggestion" of what’s happening. By looking for outflow boundaries and understanding the difference between Base and Composite reflectivity, you can navigate a Vegas monsoon like a pro. Don't let a "clear" radar screen fool you when the clouds start looking bruised; the desert always has a surprise up its sleeve.