howmuchsun

Vitamin D from sunlight in Spain

How long you need in the sun to make vitamin D, and when the sun is too low to make any at all, for 2 cities in Spain.

CityLatitudeElevationVitamin D winter
Madrid 40.42°N 665 m 5 Nov – 12 Feb (100 days)
Barcelona 41.39°N 15 m 28 Oct – 21 Feb (117 days)

How these dates are calculated