Last updated: August 1, 2025
Understanding the UV Index is crucial for residents and visitors of Hondomachi-hondo, Japan, where the March-to-November climate brings both warmth and elevated sun exposure. With UV levels peaking around midday—reaching a staggering 13—knowledge of these daily variations is essential for effective sunburn prevention and maintaining skin health. The city's humid subtropical climate (Cfa) can intensify the sun's rays, making it vital to stay informed about UV risks and take appropriate precautions. By staying aware of the UV Index, you can enjoy the beautiful outdoors while protecting your skin from harmful effects!
The UV Index for the day exhibits a striking daytime peak, rising steadily from a gentle 1 at 07:00 to an intense 13 by 12:00. As the sun reaches its zenith, the 11:00 and 12:00 hours warn of heightened exposure, with the index hitting its maximum at 13:00 before beginning its gradual decline. By 15:00, it slips to 7, reminding us that even in the afternoon, protection is vital. As the day winds down, the UV levels fall back to a safe 1 by 18:00, ensuring a return to safer conditions for evening activities. Stay vigilant and protect your skin during those midday hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 5 | moderate | 30 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index shows notable seasonal changes, with the highest risk occurring from March to September. During these months, the index reaches extreme levels, particularly peaking in August with a UV Index of 13. Visitors and residents should exercise caution during high-risk months and, ideally, limit direct sun exposure to less than 10 minutes daily between April and September. In contrast, the UV Index is relatively moderate in January and December, with burn times of 30 minutes. To minimize the risk of skin damage, it is essential to apply sunscreen, wear protective clothing, and seek shade, especially during peak hours from late morning to early afternoon.
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 |
| Hondomachi-hondo | 5 | 6 | 9 | 11 | 12 | 12 | 12 | 13 | 11 | 8 | 6 | 4 |