Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Haibara-akanedai, Japan, where the subtropical Cfa climate brings with it a unique set of sun exposure risks. As the UV levels can reach a peak of 12 during midday, being aware of these fluctuations is essential for preventing sunburn and promoting long-term skin health. Awareness of UV levels helps everyone enjoy the beautiful outdoors while protecting themselves from the harmful effects of overexposure. With the potential for high UV readings, particularly from 10 AM to 2 PM, it’s vital to take precautions during these hours to stay safe under the sun.
The UV Index climbs sharply as the day progresses, starting from a gentle 2 at 07:00 and peaking at a striking 12 between 11:00 and 12:00. This midday intensity indicates a significant risk of harm from unprotected sun exposure. As afternoon fades into evening, the index gradually decreases, dropping to 9 at 14:00, then settling at 6 by 15:00, and dwindling to 1 by 18:00. Finally, it reaches a 0 level by 19:00, making late evening a safer time to enjoy outdoor activities. Be sure to take precautions during peak hours to protect your skin from potential damage!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 10 | very high | 15 min |
| 11:00 | 12 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV exposure levels vary significantly, with the highest risks typically occurring in the late spring to summer months. From April through August, the UV Index reaches extreme levels of 11 to 12, indicating that even short exposure (as little as 10 minutes) can result in skin damage. The highest-risk months are April, May, June, July, and August, where it's crucial for both visitors and residents to take protective measures such as wearing sunscreen, hats, and protective clothing. As summer transitions to fall, UV levels begin to decline, with an Index of 10 in September, followed by 7 in October and 6 in November. Visitors and residents should remain vigilant, especially during these peak months, to ensure their safety and well-being under the sun. In the winter months (December and January), the UV Index drops to 4, indicating a moderate risk, allowing for longer burn times of 30 minutes.
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 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |
| Haibara-akanedai | 4 | 6 | 8 | 11 | 11 | 12 | 12 | 12 | 10 | 7 | 6 | 4 |