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UV Index & Sun Protection Calculator

Calculate UV exposure and sun protection needs based on altitude, latitude, and time.

Altitude (m)

Latitude (0°=equator, 90°=pole)

Cloud Cover

Time of Day

UV Index Level

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SPF Level

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Minutes to Burn

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Reapply Every

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Related Tools

UV Index Calculator for Hikers & Campers

UV radiation increases with altitude and varies by latitude, time, and cloud cover. Our calculator estimates your UV exposure and recommends SPF level, burn time, and sun protection tips for outdoor activities.

Frequently Asked Questions

Why does UV increase at altitude?

UV radiation increases approximately 10-12% for every 1,000 meters of elevation gain because there's less atmosphere to absorb UV rays. At 3,000m, UV is about 30% stronger than at sea level.

Do I need sunscreen on cloudy days?

Yes! Up to 80% of UV rays penetrate clouds. Overcast skies still allow significant UV exposure, especially at altitude or near reflective surfaces like water and snow.