Last updated: May 3, 2025
Understanding the UV Index in Yonezawa, Japan, is essential for safeguarding your skin and overall health. Elevated UV levels, especially during midday hours, can significantly increase the risk of sunburn and long-term skin damage. With Yonezawa's Dfb climate featuring warm summers and chilly winters, residents and visitors alike must remain vigilant about sun exposure. As the UV Index soars to 10 between 11:00 AM and 12:00 PM, staying informed about UV levels is critical for enjoying the outdoors safely while minimizing skin health risks. Make sun safety a priority and embrace the beauty of Yonezawa!
The UV Index for today peaks dramatically as the sun rises, beginning at a modest 2 at 07:00. The intensity quickly escalates, reaching 4 by 08:00 and soaring to 7 by 09:00. By 10:00, the index hits 9, and it reaches its zenith at 11:00 and 12:00, both clocking in at an impressive 10—indicating a high risk of harm from unprotected sun exposure. As the afternoon progresses, the index gradually declines, dipping to 9 at 13:00, then sliding to 7 at 14:00. By 15:00, it reduces to 4, and as the day winds down, the index falls to 2 at 16:00, and further to 1 by 17:00 and 18:00, before settling at a safe 0 by 19:00. Remember, it’s crucial to protect your skin during the peak hours when the UV Index is at its highest!
| 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 | 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 |
Throughout the year, UV levels demonstrate significant seasonal variations, with high-risk months typically occurring from March through August. During this period, the UV Index peaks at 11 in June, July, and August, marking it as an extreme risk category with a burn time of just 10 minutes. In contrast, the lowest UV Index readings, categorized as moderate, occur in January, February, November, and December, allowing for 30-minute exposure without immediate risk of skin damage. Visitors and residents should prioritize sun safety measures, particularly in the high-risk months—using sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize potential harm from intense UV radiation.
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 |
| Yonezawa | 3 | 5 | 8 | 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 |