howmuchsun

Vitamin D from sunlight in Ireland

How long you need in the sun to make vitamin D, and when the sun is too low to make any at all, for 15 cities in Ireland.

CityLatitudeElevationVitamin D winter
Dublin 53.33°N 17 m 23 Sep – 31 Mar (190 days)
Cork 51.90°N 10 m 27 Sep – 26 Mar (181 days)
Limerick 52.66°N 7 m 25 Sep – 28 Mar (185 days)
Galway 53.27°N 10 m 23 Sep – 30 Mar (189 days)
Tallaght 53.29°N 103 m 23 Sep – 31 Mar (190 days)
Waterford 52.26°N 10 m 26 Sep – 27 Mar (183 days)
Drogheda 53.72°N 28 m 21 Sep – 1 Apr (193 days)
Dundalk 54.00°N 18 m 20 Sep – 2 Apr (195 days)
Swords 53.46°N 17 m 22 Sep – 1 Apr (192 days)
Navan 53.65°N 35 m 22 Sep – 1 Apr (192 days)
Bray 53.20°N 7 m 23 Sep – 31 Mar (190 days)
Dún Laoghaire 53.29°N 16 m 23 Sep – 31 Mar (190 days)
Ennis 52.84°N 3 m 24 Sep – 29 Mar (187 days)
Carlow 52.84°N 55 m 24 Sep – 29 Mar (187 days)
Douglas 51.87°N 11 m 27 Sep – 26 Mar (181 days)

How these dates are calculated