What Time of Year Are We Getting Vitamin D From the Sun?
You have probably heard that the body forms vitamin D when the sun shines on our skin. But did you know that it only works in the summer? In order for the body to be able to form vitamin D from the sun’s rays, the sun must be at least 45 degrees above the horizon. Which, if you find yourself living above the 37th parallel (37 degrees latitude), it tends not to for about half of the year during the winter months of November to March. This “Vitamin D winter” gets even longer the further north you live. Take Sweden for example, where vitamin D winter can start already in September and go through April.
However during the summer months or “Vitamin D season” it’s enough to be out in the sun for about 20 minutes in the mid-day to fully charge your vitamin D deposits. Of course this varies based on skin tone, cloud cover etc., but generally speaking it doesn’t take much. And also worth noting, there’s no point in overdoing it, being out longer doesn’t translate into generating more vitamin D – which means that there is no reason to be in the sun for so long that you burn yourself and cause skin damage.