Month by month
Las Vegas weather in May
The heat switches on: almost no rain, and the year’s first 100°F days.
At a glance
May is when Las Vegas starts to feel like a desert summer. Rain is close to absent, the air is dry and the first triple-digit afternoons usually arrive. Nights are still pleasant, so mornings and evenings are the best time to be outside. This is a good month to start treating heat as a real hazard, especially for anyone hiking or exercising outdoors.
By NOAA’s 1991–2020 normals for Harry Reid International Airport, May days peak around 89°F and nights bottom out near 66°F. An average May has 2.8 days at 100°F or hotter and 15.9 days at 90°F or hotter. Normal rainfall is 0.07 inches, with 1.1 days getting at least a hundredth of an inch and 0.2 days getting a tenth of an inch or more. The median May total is 0.01 inches, so in a typical year it is drier than the average suggests: a few wet years pull the average up.
Through the day
Mornings are the sweet spot. It averages 75°F at 9 a.m. and 87°F at the 4 p.m. peak, so hikes and runs go best before noon. Evenings are pleasant too, averaging 80°F at 9 p.m.
| Time (PDT) | Normal | Cool day | Hot day |
|---|---|---|---|
| 6 a.m. | 67°F | 57°F | 75°F |
| 9 a.m. | 75°F | 64°F | 84°F |
| Noon | 82°F | 71°F | 93°F |
| 3 p.m. | 87°F | 74°F | 98°F |
| 6 p.m. | 86°F | 74°F | 97°F |
| 9 p.m. | 80°F | 69°F | 91°F |
| Midnight | 74°F | 64°F | 84°F |
"Cool day" and "hot day" are NOAA’s 10th and 90th percentiles for that hour: one May day in ten is cooler or hotter than shown. NOAA publishes hourly normals in standard time; we shifted them to clock time for daylight saving time. Hourly averages run a little below the normal daily high because the hottest moment doesn’t land on the same hour every day.
The air is dry: the average dew point across the day is about 30°F. Wind averages 10.0 mph over the day and is usually strongest around 6 p.m. (12.4 mph on average).
Over the month
May isn’t one temperature. The normal high climbs from 82.8°F on May 1 to 94.4°F on May 31, and the normal low goes from 61.2°F to 71.0°F. That 11.6° change is big enough that the start and end of the month feel different, so check the dates of your trip, not just the month.
For a specific date, the live National Weather Service forecast on our home page is more useful than any average once you are within a week of your trip.
What to pack
- Light, loose, light-colored clothing
- Sunscreen, sunglasses and a wide-brimmed hat
- A large refillable water bottle
- A light layer for air-conditioned casinos and shows
Staying safe
Heat. Heat is the deadliest weather hazard in the Southwest, according to the NWS. Drink water before you feel thirsty, avoid strenuous activity in the afternoon, and know the warning signs: heavy sweating, cramps, dizziness and nausea point to heat exhaustion, while confusion and hot skin can mean heat stroke, which is a 911 emergency. Our heat-safety guide has the NWS first-aid steps and where to find cooling stations.
Wind and dust. Strong winds from passing storm systems are most common in spring and fall here, and the blowing dust can cut visibility on the roads. Secure anything loose on balconies or patios, and slow down or pull well off the road if dust gets thick.
For current watches and warnings, follow the NWS Las Vegas office. Our resources page lists the other agencies worth knowing. In an emergency, call 911.
May records
| Record | Temperature | Date |
|---|---|---|
| Hottest | 109°F | May 28, 2003 |
| Coldest | 38°F | May 3, 1942 |
| Warmest night | 89°F | May 29, 2003 |
| Coolest day | 60°F | May 8, 1979 |
NWS Las Vegas records since January 1, 1937. Where a record has been tied, we show the most recent date. See every month on our records page.