Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Otofuke, Japan, where the climate is characterized by cold winters and warm summers typical of the Dfb zone. With maximum UV levels reaching 10 during peak hours, being aware of daily UV exposure is essential for preventing sunburn and safeguarding skin health. As the sun's intensity varies throughout the day, a strong UV Index signals a higher risk of skin damage, making it vital to take protective measures during outdoor activities. Staying informed about UV levels can help you enjoy the beautiful weather while protecting your skin from harmful rays.
The hourly UV Index paints a clear picture of the day's intensity from morning to evening. Starting at a mild 3 at 7:00 AM, the day warms up quickly, peaking at a robust 10 between 11:00 AM and 12:00 PM—the perfect time to seek shelter or apply sunscreen. After that fleeting high, the UV Index gradually declines, dropping to 4 by 3:00 PM and further diminishing to 1 by 5:00 PM. As the sun sets, the UV levels plummet to a safe 0 by 7:00 PM. This data underscores the importance of protecting your skin during peak hours, especially when the sun is at its strongest.
| 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 | 3 | moderate | 30 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV exposure levels fluctuate significantly, with the highest risks occurring during the summer months of June, July, and August when the UV Index peaks at 10 and the exposure category is classified as very high. During these months, the burn time is notably reduced to just 15 minutes, indicating the need for diligent sun protection. In contrast, the beginning and end of the year (January and December) feature low UV levels, with an index of 2 and burn times up to 45 minutes. Residents and visitors alike are advised to be particularly cautious from April through September when the UV index ranges from 8 to 10. It's crucial to take preventive measures such as wearing sunscreen, protective clothing, and seeking shade to minimize the risk of sunburn and long-term skin damage during high UV months.
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 |
| Otofuke | 2 | 3 | 5 | 8 | 9 | 10 | 10 | 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 |