Information on Vitamin D Synthesis / Erythemal UV

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

Exposure Time around Noon (min.)
January February March
early middle late early middle late early middle late
MED 100 100 100 100 90 70 70 65 45
600 cm2 55 50 45 40 35 30 40 25 15
1200 cm2 30 25 20 20 20 15 15 10 8

April May June
early middle late early middle late early middle late
MED 50 50 40 35 30 30 40 35 40
600 cm2 20 20 15 15 10 10 15 15 15
1200 cm2 10 9 7 6 6 6 7 6 7

July August September
early middle late early middle late early middle late
MED 40 30 30 25 30 40 45 50 45
600 cm2 15 9 10 9 10 15 15 20 15
1200 cm2 7 5 5 5 5 8 8 9 8

October November December
early middle late early middle late early middle late
MED 55 60 60 80 100 150 100 150 150
600 cm2 20 25 25 30 40 60 50 65 60
1200 cm2 10 15 15 15 20 30 25 35 30

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 Tsukuba