Why are the sun’s UV rays more harmful in the afternoon than in the morning or evening?

Question

I always hear that we should avoid the sun or make sure to put on sunscreen in the afternoon when the sun is the most intense. Why is the sun’s rays more harmful when it is directly overhead vs in the morning soon after sunrise? Either way, the sun is shining directly on me so not sure what causes the difference in intensity.

In: Planetary Science

Answer 1

You get more UV in the hours around noon when the sun’s rays travel through less atmosphere. This is why most recommendations for avoiding exposure give ranges like 9 am to 3 pm.