Last updated: May 3, 2025
Understanding the UV Index is essential for residents and visitors in Katashina, Japan, where the climate invites ample sunshine, especially in the summer months. With peak UV levels reaching up to 11 during midday, being aware of the UV Index can help you prevent sunburn and safeguard your skin health. As Katashina experiences a Dfb climate, characterized by warm summers and cold winters, knowing the daily UV exposure risks empowers you to enjoy the outdoors responsibly. Stay informed and protect yourself from harmful UV rays!
As the day unfolds, the UV Index climbs steadily, peaking at 11 between 11:00 and 12:00, signaling a strong need for sun protection during these hours. Starting from a mild 3 at 07:00, the intensity rapidly rises, reaching a noticeable 5 by 08:00 and soaring to 9 by 10:00. However, the sun's intensity begins to wane in the afternoon, dropping to 7 and then 5 from 13:00 to 15:00. By 16:00, the UV Index retreats to 3, and as evening sets in, it diminishes further to 1 by 17:00 and falls to 0 by 19:00. It's crucial to stay vigilant during those peak hours to enjoy the sun safely!
| 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 | 11 | extreme | 10 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 min |
| 15:00 | 5 | moderate | 30 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
As the seasons change, so does the UV Index, which is crucial for both visitors and residents to monitor for sun safety. January starts with a moderate UV Index of 4, allowing for a burn time of 30 minutes, but by February, the index rises to 6, categorized as high, with a shorter burn time of 25 minutes. The peak UV exposure occurs from March through August, reaching an extreme UV Index of 11, where just 10 minutes of unprotected sun exposure can lead to burns. April and May hold particularly high risks, with values of 10 and 11, respectively. Although the risk decreases in September to 10 (very high) and October to 7 (high), caution is still necessary. By November and December, the UV Index falls back to 5 and 3, categorized as moderate, allowing for 30 minutes of exposure. It is essential for all to use sunscreen and protective clothing, especially during the high-risk months of March through August, to minimize skin damage while enjoying outdoor activities.
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 |
| 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 |
| Katashina | 4 | 6 | 9 | 10 | 11 | 11 | 11 | 11 | 10 | 7 | 5 | 3 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |