Many factors , such as your skin type, the time of day, and where you reside, might affect how much time you need to spend in the sun to receive enough vitamin D. You should expose your face, arms, legs, or back to the sun for five to thirty minutes every two to three days. Depending on the intensity of the sun’s ultraviolet B (UVB) radiation, which varies depending on the time of day, the season, and your latitude, different amounts of time may be needed to create enough vitamin D.