UV and sun protection guides

Plain-English answers about the UV index, when the sun is strongest, and how to stay protected outdoors, from city days to the trail.

• What Is the UV Index? A Plain-English Guide to the Scale

  The 0 to 11+ scale explained: what each level means, why 3 is the number to remember, and what changes the reading.

• What to Wear Hiking for Sun Protection: A Practical Guide

  Clothing, hats, sunglasses and sunscreen for the trail, what UPF means, and the spots hikers forget.

• UV at Altitude, Snow and Clouds: Why You Burn Faster

  Why the sun burns faster on a mountain, how snow and water reflect UV, and what clouds really do.

• When Is UV Strongest During the Day? Best Times to Hike

  UV peaks near midday, not at the hottest hour. How to read the daily curve and time your hike around it.