On Wed, 28 Aug 2019 20:18:23 +0100, Martin Brown, another mentally
deficient, troll-feeding, senile idiot, blathered again:

Then why don't we get a lot more suntan and sunburn in the evening?
Those happen at midday.

It is the ratio of diffuse UV and blue light scattered from a clear sky
to the low light level of dusk. In direct sunlight there is a lot more
UV but there is much more visible light too. When the sun goes down the
mid band visible light decreases fastest leaving some reds and UV.

The intensity is well down but the proportion of UV is much higher.

You like talking to idiots, senile idiot? That's typical of senile idiots,
you know! BG