In the UK it's impossible to get Vitamin D from the Sun during Winter months, due to the high latitudes (it's above all of the US apart from Alaska, and is also

In the UK it's impossible to get Vitamin D from the Sun during Winter months, due to the high latitudes (it's above all of the US apart from Alaska, and is also above most of the population of Canada), even if you walk around naked at noon for an hour! Doctors here recommend everyone to take supplements. From what I recall the season is from mid October to mid March. There's a few Vitamin D online calculators about if you're curious about where you live, also.