howmuchsun

Vitamin D from sunlight in Bulgaria

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 Bulgaria.

CityLatitudeElevationVitamin D winter
Sofia 42.70°N 562 m 25 Oct – 24 Feb (123 days)
Plovdiv 42.15°N 163 m 26 Oct – 23 Feb (121 days)
Varna 43.22°N 83 m 22 Oct – 27 Feb (129 days)

How these dates are calculated