Last updated: August 1, 2025
In Nagatoro, Japan, staying informed about the UV Index is crucial for protecting your skin and preventing sunburn. With a climate classified as Cfa, the summertime temperatures in this scenic town often lead to elevated UV exposure, especially during midday when the index peaks at a striking 12. Understanding UV levels is vital not just for immediate skin protection, but also for long-term skin health. As the sun's rays can be deceptively potent, particularly between 10:00 AM and 2:00 PM, knowing when to seek shade or apply sunscreen can make all the difference for both residents and visitors alike. Stay vigilant, enjoy the beautiful outdoors, and safeguard your skin from harmful rays!
As the day begins, UV Index levels start low at 2 by 7:00 AM, making for a gentle morning. However, the sun rises higher, and by 10:00 AM, the intensity peaks at a powerful 10, reaching a maximum of 12 by 12:00 PM. This intense UV exposure is most pronounced at 11:00 AM, where it reaches 11. As the afternoon unfolds, the UV Index gradually declines; it slips to 8 by 2:00 PM and continues to drop, tapering to 6 at 3:00 PM before settling down to a mild 1 by 5:00 PM. By evening, the UV risk diminishes further, reaching 0 by 7:00 PM, signaling a safe end to the day's sun. Ideal for planning outdoor activities, this data underscores the importance of sun protection during peak hours!
| 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 | 11 | extreme | 10 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 8 | very high | 15 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 |
Throughout the year, the UV Index demonstrates notable seasonal changes, with the most intense exposure occurring from April to August. During these months, the UV Index reaches extreme levels (10-12), significantly reducing the burn time to just 10 minutes. March and September also pose risks with very high levels (8-10), allowing for a burn time of only 15 minutes. Consequently, February and October present high levels (6-7), where protective measures are still advised with adjusted burn times of 25 minutes. Residents and visitors should exercise caution and protect their skin, especially during the high-risk months of April through August, by using sunscreen, wearing protective clothing, and limiting sun exposure during peak hours.
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 |
| Nagatoro | 4 | 6 | 8 | 10 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 4 |