UV index and sunburn time in Japan
Peak UV index and how quickly unprotected skin burns, for 9 cities in Japan.
| City | Peak UV | Category | Month | Burns after |
|---|---|---|---|---|
| Tokyo | 10.4 | Very high | July | 22 min |
| Yokohama | 10.5 | Very high | July | 22 min |
| Osaka | 10.6 | Very high | July | 22 min |
| Nagoya | 10.4 | Very high | July | 22 min |
| Sapporo | 8.5 | Very high | July | 27 min |
| Fukuoka | 11.0 | Very high | July | 21 min |
| Kawasaki | 10.4 | Very high | July | 22 min |
| Kobe | 10.6 | Very high | July | 22 min |
| Kyoto | 10.5 | Very high | July | 22 min |
The same UV also drives vitamin D synthesis — and stops entirely for part of the year at higher latitudes. Vitamin D winters in Japan →
Burn times are for skin type III with no sunscreen. How these are calculated