Last updated: August 1, 2025
In Shimanto, Japan, awareness of the UV Index is crucial for safeguarding your skin and overall health. Understanding UV levels is essential to prevent sunburn and reduce the risk of skin damage. With a Cfa climate that brings warm summers and significant sun exposure, the UV Index can peak at a striking 12 around noon. This means it’s vital for residents and visitors alike to stay informed about daily UV variations to enjoy the outdoors safely while protecting their skin from harmful rays.
The UV Index throughout the day reveals a striking pattern of solar intensity. Starting at 07:00, the index is a manageable 2, but it quickly climbs as the sun rises higher. By 08:00, it's at 4, and by 09:00, it reaches 6, signaling a push towards midday sun. The peak intensity strikes at 12:00 with a blistering 12, making it essential to seek shade and wear sunscreen. From this zenith, the index gradually declines: 11 at 13:00, 10 at 14:00, and finally dipping to 7 by 15:00. As daylight wanes, the UV levels fall rapidly, resting at 2 by 17:00 and dropping to a safe 1 by 18:00 and 19:00. Enjoy the sun, but be mindful of those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | 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 | 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 varies significantly, with the highest levels observed from March to September, indicating a seasonal increase in UV radiation. During this period, visitors and residents should be particularly cautious, as the UV Index reaches extreme levels of 12, especially from May to August, with a burn time as brief as 10 minutes. Even in October and November, the UV Index remains elevated, categorized as very high and high, respectively. To ensure safety, it's advisable to wear protective clothing, apply broad-spectrum sunscreen, and seek shade during peak sun hours, particularly in high-risk months from April to September. As the year progresses, individuals can take advantage of the lower UV indices from December to February, when burn times increase to 30 and 25 minutes, making sun safety less critical but still important.
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 |
| Shimanto | 4 | 6 | 9 | 10 | 12 | 12 | 12 | 12 | 11 | 8 | 6 | 4 |