Places / Haleakalā
UV index at Haleakalā National Park, Hawaiʻi
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 Haleakalā
Haleakalā rises 3,055 metres (10,023 feet) from the sea on Maui, at about 21° north. Visitors drive from the coast to above the clouds in a couple of hours, and the summit’s cool air can hide extremely strong tropical sun.
Elevation and your real UV
The forecast on this page covers the general area around Haleakalā. Weather models don’t resolve individual peaks and valleys, so treat it as a sea-level reading. 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 |
|---|---|---|
| Sea level | 0 m | Baseline |
| The summit | 3,055 m (10,023 ft) | about 31% to 37% 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 sun is high all year at this latitude, so UV is strong in every season. Low cloud often sits below the summit, which can leave the crater bathed in clear, intense sunlight while the coast looks overcast.
On the trail
Trails like Sliding Sands descend into a volcanic crater with almost no shade. The landscape is bare cinder and rock, and hikers spend hours in open terrain. Because you start at over 3,000 metres, you begin with much more UV than at the beach.
Sun protection tips for Haleakalā
- Cool temperatures at the summit make it easy to forget sun protection. Put it on anyway.
- Sunrise visitors get low UV at first, but it climbs quickly once the sun is up.
- Bring a brimmed hat and sunglasses for the crater. There is no shade to speak of.
- At the summit you’re over 3,000 m above sea level, so expect roughly a third more UV than at the coast.
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.