Where are you getting this information? My understanding is that Vitamin D production in the body is correlated with the directness of the exposure to the sun - therefore the most D is made at solar noon.
Yes and for example in central europe, you won't get enough UV-B from the sun in the winter months at all, as it is filtered out by the atmosphere (low angle, more atmosphere to pass through). But in the sommer, one still should avoid the sun at noon, because of sun burns.
I'm not sure where I read that but it turns out to be wrong, after reading a bit it seems noon is a good time but is also the most dangerous time due of the high amount amount of UVB.
