From what I’ve read, light skinned people near the equator is about 13 minutes during noon time sun at least 3 times a week. Dark skinned people is 3 to 4 times that amount. People in my neck of the woods can’t get enough sun to get vitamin D synthesis to occur for about 5 months out of each year.
I used to travel a lot, be gone for months, and every time I came home you could literally feel the sun reach inside you.