Last updated: July 2, 2025
In Hitoyoshi, Japan, staying informed about the UV Index is crucial for safeguarding your skin from harmful ultraviolet rays. Understanding UV levels helps in preventing sunburn and maintaining overall skin health, especially as the sun can be particularly intense during the summer months. With a Cfa climate characterized by warm, humid summers, residents and visitors face notable UV exposure risks, particularly between 11:00 AM and 1:00 PM, when the index peaks at a staggering 13. Being aware of these levels empowers you to take necessary precautions and enjoy the beautiful outdoors safely.
The UV Index exhibits a dynamic range throughout the day, starting at a mild level of 2 at 7:00 AM. As the sun rises higher, it peaks at an intense 13 by 12:00 PM, indicating a significant risk of harm from unprotected sun exposure. From there, it begins a gentle decline, dropping to 10 at 2:00 PM and gradually tapering off to 1 by the evening hours. The highest figures, 11 and 13, underscore the importance of applying sunscreen and wearing protective clothing during midday. As the day unfolds, be sure to take precautions during peak UV hours to ensure your safety in the sun!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 13 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV Index levels fluctuate, indicating varying sun exposure risks. High-risk months are predominantly from March to September, where the UV Index frequently reaches extreme levels (10-13), with May to August being critically important, showing consistent values of 12 or higher. In March, the UV Index rises sharply to 9, followed by April and May with values of 10 and 12 respectively. It's vital for residents and visitors to understand that during this period, burn times decrease significantly to just 10 minutes, necessitating proactive sun safety measures such as wearing sunscreen, protective clothing, and seeking shade, especially between 10 AM and 4 PM. As the year progresses into the fall, UV levels gradually decline, but caution is still advised in October when the index remains high at 8. In winter, UV exposure returns to moderate levels, allowing for longer burn times in January and December, yet awareness and prevention remain essential year-round.
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 |
| Hitoyoshi | 5 | 6 | 9 | 10 | 12 | 12 | 13 | 13 | 11 | 8 | 6 | 4 |