Posts Tagged ‘uvb’

Vitamin D Producing UVB Rays from the Sun

The sun’s rays that shine down upon us are UVA and UVB ultraviolet rays.

But only the UVB rays are vitamin D producing when they hit your skin.

Little known is that everyone living north of 35° latitude will get no UVB rays between the months of November through March because of the angle of the sun.

To give you some prospective, New York City, NY is in 40° latitude and Flagstaff, AZ is in 35° latitude.  Fully two/thirds of the U.S and all of Canada are above the 35° latitude mark.

As a further reference, the equator is at 0° latitude and gets the benefit of the highest level of the sun’s UVB rays, whereas the North Pole is at 90° latitude and gets the least benefit.

We do not get the same amount of UVB rays year round. As the seasons change, so does the angle of the sun’s rays.

In the summer, with the sun directly overhead, we get the maximum number of UVB rays.  As the season moves toward winter, we get fewer and fewer rays and in the winter, if you live in 35° latitude and above, you will get no UVB rays at all.

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