Mar 21, Happy Vernal Equinox! Spring is just around the corner for most of the northern hemisphere, and with that comes the promise of long and. How much time do I have to go for a bike ride in Enter a location to view its sunrise, sunset and total daylight time for any day of the of daylight Sun /07/ of daylight of daylight Jun 23, In the winter, it's impossible to produce vitamin D from the sun if you live north experts say going outside for 10 minutes in the midday sun—in shorts and a winter of about 2, IUs per day and a dose of daily sunshine in the summer. It also depends on how much skin is exposed and the time of day. What Exactly Does The Sun Do To Your Skin?