Last updated: May 3, 2025
In Oi, Japan, being aware of the UV Index is crucial for protecting your skin from potential damage caused by the sun. Understanding UV levels is essential not only for preventing painful sunburns but also for maintaining long-term skin health. With a Cfa climate characterized by hot, humid summers, residents and visitors in Oi must remain vigilant as UV exposure peaks, particularly around midday when the index can reach as high as 11. By staying informed about the UV Index, you can enjoy the beautiful weather while keeping your skin safe from harmful rays.
As the sun rises, the UV Index begins its ascent, reaching a gentle 2 by 07:00. By 08:00, it climbs to a moderate 5, signaling the start of a day to be mindful of sun exposure. The intensity peaks at 11 from 11:00 to 12:00, marking the golden hours when protective measures are crucial. As the afternoon unfolds, the value dips to 9 at 13:00 and continues its descent to 7 by 14:00. By the late afternoon, the UV Index relaxes significantly, falling to 4 at 15:00 and tapering off to 2 by 16:00. As the sun sets, it becomes a safe 1 at 17:00, finally reaching a calm 0 after 19:00. This data highlights the importance of sun safety practices during peak hours, especially between 10:00 and 14:00.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 5 | 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 | 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 |
As the seasons change, the UV Index fluctuates significantly, influencing the risk of sun exposure throughout the year. January and February start with a moderate UV Index of 3 and 5, allowing for a burn time of 30 minutes. However, by March, the UV Index jumps to 8, which is categorized as very high, reducing safe exposure to just 15 minutes. The peak months for UV radiation are May through August, where the Index reaches an extreme level of 11, necessitating a mere 10 minutes of exposure before risking sunburn. September begins a gradual decline to a very high index of 10, while October and onward return to moderate levels. Visitors and residents should be particularly cautious from March to August—wearing protective clothing, applying sunscreen, and seeking shade to minimize UV damage during these high-risk 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 |
| Oi | 3 | 5 | 8 | 9 | 11 | 11 | 11 | 11 | 10 | 7 | 5 | 4 |
| 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 |