howmuchsun

Vitamin D from sunlight in South Korea

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 South Korea.

CityLatitudeElevationVitamin D winter
Seoul 37.57°N 38 m 12 Nov – 6 Feb (87 days)
Busan 35.10°N 15 m 24 Nov – 24 Jan (62 days)
Incheon 37.46°N 43 m 12 Nov – 5 Feb (86 days)
Daegu 35.87°N 45 m 20 Nov – 28 Jan (70 days)
Daejeon 36.35°N 58 m 17 Nov – 31 Jan (76 days)
Gwangju 35.15°N 47 m 24 Nov – 24 Jan (62 days)
Suwon 37.29°N 58 m 13 Nov – 4 Feb (84 days)
Ulsan 35.54°N 10 m 21 Nov – 26 Jan (67 days)

How these dates are calculated