howmuchsun

Vitamin D from sunlight in Turkey

How long you need in the sun to make vitamin D, and when the sun is too low to make any at all, for 8 cities in Turkey.

CityLatitudeElevationVitamin D winter
Istanbul 41.01°N 39 m 30 Oct – 19 Feb (113 days)
Ankara 39.92°N 850 m 6 Nov – 11 Feb (98 days)
Bursa 40.20°N 155 m 2 Nov – 15 Feb (106 days)
İzmir 38.41°N 122 m 9 Nov – 8 Feb (92 days)
Gaziantep 37.06°N 842 m 19 Nov – 29 Jan (72 days)
Diyarbakır 37.91°N 674 m 15 Nov – 2 Feb (80 days)
Adana 36.99°N 30 m 16 Nov – 31 Jan (77 days)
Kayseri 38.73°N 1,054 m 12 Nov – 5 Feb (86 days)

How these dates are calculated