Information on Vitamin D Synthesis / Erythemal UV

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

Exposure Time around Noon (min.)
January February March
early middle late early middle late early middle late
MED 60 65 55 55 40 35 45 35 30
600 cm2 20 25 20 20 15 15 15 15 10
1200 cm2 10 15 10 10 8 6 8 7 5

April May June
early middle late early middle late early middle late
MED 25 25 30 25 25 20 20 20 15
600 cm2 9 9 10 9 8 7 7 7 6
1200 cm2 5 5 5 5 4 4 4 4 3

July August September
early middle late early middle late early middle late
MED 15 15 20 20 20 20 20 20 20
600 cm2 6 6 6 6 6 6 7 7 7
1200 cm2 3 3 3 3 3 3 4 4 4

October November December
early middle late early middle late early middle late
MED 20 25 30 35 40 45 60 70 60
600 cm2 7 8 10 15 15 15 20 25 20
1200 cm2 4 4 5 6 7 8 10 15 10

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 Hateruma