howmuchsun

Vitamin D from sunlight in Puerto Rico

How long you need in the sun to make vitamin D, and when the sun is too low to make any at all, for 3 cities in Puerto Rico.

CityLatitudeElevationVitamin D winter
San Juan 18.47°N 7 m none
Bayamón 18.40°N 16 m none
Carolina 18.38°N 16 m none

How these dates are calculated