Last updated: August 1, 2025
In Unnan, Japan, staying informed about the UV Index is crucial for protecting your skin from harmful ultraviolet rays. Understanding UV levels can significantly aid in sunburn prevention and overall skin health, helping residents and visitors alike make informed decisions about sun exposure. With a Cfa climate, Unnan experiences warm summers that can lead to heightened UV risks, especially during midday hours when the index peaks at a staggering 12. By being aware of the UV Index and taking proper precautions, you can enjoy the beautiful outdoors while safeguarding your skin.
The UV Index begins its rise at 7:00 AM with a low of 2, gradually climbing to a moderate 3 by 8:00 AM. By 9:00 AM, it reaches 6, but it's at 10:00 AM when the sun truly bears down, peaking at a high of 9. The intensity continues to soar, hitting a maximum of 12 at 12:00 PM, making it the most UV-active hour of the day. From there, it subtly declines, dropping back to 11 at 1:00 PM, and 9 at 2:00 PM. The afternoon brings relief as the index falls to 6 by 3:00 PM and continues to decrease, settling at 4 by 4:00 PM. As the day winds down, the UV Index dips to 2 by 5:00 PM and further to a safe 1 by 6:00 PM and stays consistent through 7:00 PM. Stay sun-smart and avoid peak UV hours for your skin's safety!
| 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 | 8 | very high | 15 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 11 | 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, the UV Index experiences notable fluctuations, with significant increases during the spring and summer months. March marks the beginning of high-risk UV exposure, peaking in July and August at a severe UV Index of 12, where the recommended burn time is just 10 minutes. Both April and May maintain an extreme category, urging outdoor enthusiasts to exercise caution. From September onward, UV levels gradually decline, but the risk remains high into early fall. Residents and visitors are advised to protect themselves, especially during the high-risk months of March to September, by applying sunscreen, wearing protective clothing, and seeking shade to minimize sun exposure. As the year progresses, understanding and adapting to these changes can help ensure safety and enjoyment in outdoor activities.
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 |
| Unnan | 4 | 5 | 8 | 11 | 11 | 11 | 12 | 12 | 10 | 7 | 5 | 3 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |