[Black Agnes]

LOL

https://www.esrl.noaa.gov/gmd/grad/solcalc/azel.html

If solar elevation is at least 50deg, you’ll make vitamin D in the sun.

[steve86]

I used to get pretty badly sunburned (face) on winter ski trips, sometimes up in British Columbia. And I have a medium olive complexion. Of course, reflection off the snow and elevation/altitude has a lot to do with that.