When I was younger I often spent two weeks at Christmas on the Yucatan Peninsula touring the ruins. At the time, I believed that I was treating myself of SAD with a 'sunshine therapy.'
Turns out I probably was because of a Vitimin D deficiency....now that I take daily doses of vitamin D, no SAD problems. So.....many benefits of taking vitamin D.
BTW, lack of vitamin D is why people turned 'White'.
There really is nothing better than being in the sun under the blue sky. I'm so sick of Winter!