Thread

1. xattt · 1790112634 · focus · HN ↗

   I am curious if anyone else can tell whether it is a high UV day just by looking outside.

   There is a certain look to the sky (slightly whiter-bluer) looking against the clouds, and I am not sure if it is because I am directly seeing UV, whether there is some fluorescence, or whether it’s placebo effect.

   1. pazimzadeh · 1790113072 · focus · HN ↗

      UV index weighs UVB more heavily than UVA. UVB falls much faster than UVA and visible sunlight as the sun gets lower because photons travel through increasingly more ozone and atmosphere. So the higher in the sky the sun is, minus cloud clover, the higher the UV index is.

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