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

Using DST, on average the suns rays will be most direct at 1pm, depending on where you live. It’s still going to be pretty direct at 12pm and 2pm but the further you get from solar noon, the more atmosphere the suns rays have to go through because it comes in at more of an angle. Gasses in the atmosphere can absorb a portion of the UV radiation.