Places / Grand Canyon South Rim
UV index at Grand Canyon South Rim, Arizona
Check another placeLoading today’s UV…
- Low 0 to 2
- Moderate 3 to 5
- High 6 to 7
- Very high 8 to 10
- Extreme 11+
Hour-by-hour numbers
| Time | UV index | Level |
|---|
The next few days
Each day’s UV curve and peak, drawn on the same scale so you can compare. The forecast reaches roughly four days ahead.
What to do today
About Grand Canyon South Rim
The South Rim sits at about 7,000 feet (2,100 m), so you’re already in stronger UV than at sea level before you take a step. The canyon is wide open, with big sky and very little shade.
Elevation and your real UV
The forecast on this page covers the general area around Grand Canyon South Rim, at about 7,000 ft. Weather models don’t resolve individual features, so treat the chart as a guide for the rim. Elevation gains on the main trails are modest compared with the effect of open sky, bare rock and heat. The WHO says UV rises by 10% to 12% for every 1,000 metres you climb, which is a useful rule of thumb on any high route. See UV at altitude, on snow and under clouds.
When UV is strongest here
Clear skies are common through the year, so strong UV isn’t limited to summer. In summer the inner canyon is dominated by heat. In winter, snow can lie on the rim and along upper trails, adding reflection.
On the trail
Trails like Bright Angel and South Kaibab drop below the rim into steep, exposed terrain. The river sits far lower, at roughly 2,400 feet, so altitude adds less UV down there, but heat and reflected light from the rock walls make the exposure harsher. Every hike is out and back, and the climb out often falls in the afternoon sun.
Sun protection tips for Grand Canyon South Rim
- Start early. The National Park Service advises against day hikes from the rim to the river and back in summer heat.
- A loose UPF long-sleeve shirt is cooler than bare skin in dry heat.
- Use shaded spots along the trail for breaks and reapplication.
- Plan your return so you’re not climbing out in the strongest sun.
Similar places
Related guides
- What to Wear Hiking for Sun Protection: A Practical Guide
- UV at Altitude, Snow and Clouds: Why You Burn Faster
- When Is UV Strongest During the Day? Best Times to Hike
Elevations are rounded published figures. UV forecasts are model estimates for the area and can differ from what you experience on the ground. This is general information about sun safety and isn’t medical advice. Last updated September 20, 2026.