Places / Mount Whitney
UV index at Mount Whitney, California
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 Mount Whitney
Mount Whitney is the highest summit in the contiguous United States at 14,505 feet (4,421 m). Most hikers start at Whitney Portal, already at about 8,400 feet, and climb roughly 6,100 feet more on a long day.
Elevation and your real UV
The forecast on this page covers the general area around Mount Whitney. Weather models don’t resolve individual peaks and valleys, so treat it as the level of Whitney Portal (8,374 ft). The WHO says UV rises by 10% to 12% for every 1,000 metres you climb. Using that rule of thumb:
| Place | Elevation | Compared with baseline |
|---|---|---|
| Whitney Portal | 2,552 m (8,374 ft) | Baseline |
| The summit | 4,421 m (14,505 ft) | about 19% to 22% more UV |
Read the peak UV from the chart above, then adjust it up for where you’ll actually be. There’s a worked example in UV at altitude, on snow and under clouds.
When UV is strongest here
The main season runs from summer into early autumn, when the trail is usually clear of snow. Snow and ice can linger on the upper trail into early summer. Permits are required, so check with the Inyo National Forest before you plan.
On the trail
The trail climbs from forest into rock and scree above treeline. The upper miles, including the switchbacks and the summit plateau, offer no shade at all. It’s a very long day, which means many hours under high-altitude UV.
Sun protection tips for Mount Whitney
- Most hikers start before dawn, which puts the summit hours before or around the midday peak.
- Reapply on the way up, at the summit and again on the descent. It’s a long day.
- Wear a hat with neck coverage. The back of the neck takes a beating on the switchbacks.
- Carry sunglasses with side shields in case you meet lingering snow near Trail Crest.
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.