Last updated: May 3, 2025
In the picturesque town of Shirakawa, Japan, awareness of the UV Index is crucial for protecting your skin from harmful sun exposure. With UV levels ranging from a moderate 3 in the morning to a peak of 10 during midday, understanding these fluctuations can help you prevent sunburn and promote long-term skin health. Shirakawa, located in a Cfa climate zone, typically experiences a fair amount of sunshine, making it essential for residents and visitors alike to stay informed about UV risks, especially during the sunniest hours between 10 AM and 2 PM. Stay sun-smart and enjoy your time outdoors while safeguarding your skin!
In the morning, the UV Index starts off relatively low, peaking at 3 by 7 AM. As the day progresses, it steadily climbs, reaching a notable high of 10 at both 11 AM and 12 PM—this is the time to be cautious! The index then begins to dip and falls back to a moderate level of 4 by 3 PM, before dwindling to 1 by 5 PM, and finally settling at 0 by 7 PM. For those enjoying outdoor activities, it’s essential to stay sun-smart during the mid-day hours when UV radiation is at its peak!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 5 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 min |
| 15:00 | 4 | moderate | 30 min |
| 16:00 | 2 | low | 45 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
The seasonal UV variations indicate a significant increase in UV exposure from winter to summer, with high-risk months emerging from April through August. During this period, the UV Index peaks at 11 (extreme), particularly in June, July, and August, where the burn time drops to just 10 minutes. Visitors and residents are advised to take precautionary measures during these months, such as seeking shade, wearing protective clothing, and applying sunscreen frequently. As the UV levels decrease in the fall and winter months, with indices dropping to 3 in January and December, the risk of sunburn diminishes. However, maintaining sun safety practices year-round remains essential for health and well-being.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sapporo UVI | 2 | 3 | 6 | 7 | 9 | 9 | 9 | 10 | 8 | 5 | 3 | 2 |
| Shirakawa | 3 | 5 | 7 | 9 | 10 | 11 | 11 | 11 | 9 | 7 | 5 | 3 |
| Yokohama UVI | 3 | 5 | 8 | 9 | 11 | 11 | 11 | 11 | 10 | 7 | 5 | 4 |
| Tokyo UVI | 3 | 5 | 8 | 9 | 11 | 11 | 11 | 11 | 10 | 7 | 5 | 4 |
| Nagoya UVI | 4 | 6 | 8 | 10 | 11 | 11 | 11 | 11 | 10 | 7 | 5 | 3 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |