From roughly July through September, moist air surges into the desert Southwest. Afternoon thunderstorms build over mountains and mesas, bringing lightning, rainbows, virga and some of the most colorful sunsets of the year.
The daily rhythm
- Mornings are often clear.
- Cumulus towers build by midday over high terrain.
- Storms peak in the afternoon and evening, then drift and decay.
- Sunsets under clearing storms can be extraordinary as light slips under the anvils.
Where
- Grand Canyon rims and the Painted Desert in Arizona.
- Monument Valley and the mesas of northern Arizona.
- The Sonoran Desert around Tucson and Phoenix, with saguaros against storm light.
- Northern New Mexico's high desert.
Lightning safety
Stay well away from rims, ridges and isolated high points when storms are near; the Grand Canyon rims see frequent strikes. Shoot from a vehicle or sheltered position, and follow the 30/30 rule from our storm photography guide.
Flash floods
Monsoon rain far upstream can send floods through dry washes and slot canyons with little warning. Don't enter slot canyons or camp in washes when storms are possible anywhere in the watershed. See the slot canyon guide.
Photo ideas
- Rain shafts and virga lit by low sun.
- Rainbows opposite the setting sun after a storm passes.
- Wet slickrock reflecting the sky.
- Desert blooms that follow summer rains.
- Lightning over distant mesas at night.
Check cloud cover at sunset with the sunset forecast.
About 1 min read · Updated 2026-10-20