Information on Vitamin D Synthesis / Erythemal UV

Japanese

Exposure Time for Vitamin D Synthesis / MED (Climatology):Rikubetsu

Exposure Time around Noon (min.)
January February March
early middle late early middle late early middle late
MED 250 250 200 150 150 100 100 90 70
600 cm2 150 150 100 90 70 50 50 35 30
1200 cm2 80 70 55 45 35 25 25 20 15

April May June
early middle late early middle late early middle late
MED 65 65 50 50 45 40 40 50 40
600 cm2 25 25 15 20 15 15 15 20 15
1200 cm2 15 15 8 9 8 7 8 9 7

July August September
early middle late early middle late early middle late
MED 35 30 40 35 40 40 50 60 60
600 cm2 15 10 15 15 15 15 20 25 20
1200 cm2 6 6 7 6 8 7 9 10 10

October November December
early middle late early middle late early middle late
MED 70 100 100 150 200 250 300 300 300
600 cm2 25 40 50 80 100 150 150 200 200
1200 cm2 15 20 25 40 50 65 80 90 90

The numerical values in the row of 'MED', '600 cm2' and '1200 cm2' show the mean time to reach MED (Minimal Erythema Dose), the time required for 10 µg Vitamin D to be produced for a skin area of 600 cm2, and 1200 cm2 exposed to solar radiation in minutes, respectively.
By clicking each 10 day period, you can also see a diurnal variation of exposure time for that period.

Appropriate exposure time at every site shown below can be seen.
Cape Ochi-ishi (Hokkaido), Rikubetsu (Hokkaido), Sapporo (Hokkaido), Aomori (Aomori), Tsukuba (Ibaraki), Yokohama (Kanagawa), Nagoya (Aichi), Otsu (Shiga), Osaka (Osaka), Miyazaki (Miyazaki), Cape Hedo (Okinawa), Hateruma (Okinawa).

Position of Rikubetsu