Weather Whys: Why is the sun more intense at elevation?

Weather Whys

COLORADO SPRINGS, Colo. — The sun’s rays are stronger at elevation–something we notice daily in southern Colorado. You can burn much quicker if you are not careful to take care of your skin.

This is not because we are closer to the sun. Yes, Colorado has the highest average elevation of all 50 states at 6,800′, but the sun is over 96 million miles away. Even from our highest 14er, the extra elevation doesn’t make a dent in that distance.

However, the elevation does impact how much atmosphere sits above us. The Earth’s atmosphere is about 300 miles thick, a lot less than 19 million miles, and most of that is in the bottom 10 miles.

When you go up in elevation, there is less atmosphere above you. The atmosphere is what filters out much of the UV rays that come from the sun. The more atmosphere they travel through, the more UV rays are filtered out. (Sun angle also plays a role, which impacts intensity seasonally and based on latitude, but we won’t focus on that here.)

This makes a big difference when you consider that for every 1,000′ you gain in elevation, the sun’s rays can intensify by around 4%. This means that compared to sea level, Colorado’s UV exposure can be around 20% higher on average–and more if you are on a 14er.

Protect your skin:

  • Wear SPF every day
  • Reapply sunscreen
  • Find some shade
  • Wear UV blocking sunglasses
  • Wear hats

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