Information on Vitamin D Synthesis / Erythemal UV

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

Exposure Time around Noon (min.)
January February March
early middle late early middle late early middle late
MED 90 90 80 70 55 70 55 50 45
600 cm2 40 40 30 25 20 25 20 15 15
1200 cm2 20 20 15 15 10 15 10 8 8

April May June
early middle late early middle late early middle late
MED 40 35 35 35 30 30 30 30 40
600 cm2 15 10 10 15 10 10 10 10 15
1200 cm2 7 6 6 6 5 5 5 5 7

July August September
early middle late early middle late early middle late
MED 30 25 30 30 35 30 40 60 50
600 cm2 9 9 10 9 10 10 15 20 20
1200 cm2 5 5 5 5 6 5 7 10 9

October November December
early middle late early middle late early middle late
MED 50 60 70 60 80 90 90 100 100
600 cm2 20 25 25 25 35 35 35 40 40
1200 cm2 9 10 10 10 15 20 20 20 20

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 Yokohama