Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Yuza, Japan, especially in a climate zone classified as Cfa, which typically experiences warm summers and mild winters. As UV levels can soar, particularly around midday—reaching a peak of 10 between 11:00 AM and 12:00 PM—being aware of these values is essential for sunburn prevention and skin health. Awareness and proactive measures can significantly reduce the risk of harmful effects from ultraviolet radiation, making it vital to check the UV Index daily to enjoy the outdoors safely in this picturesque region.
As the sun rises, the UV Index begins to climb steadily. At 7:00 AM, it registers a mild level of 2, but by 8:00 AM, it escalates to 4, indicating the start of a more intense sun exposure. The peak occurs at 11:00 AM and 12:00 PM, where it reaches a soaring 10, alerting everyone to take necessary precautions. After midday, the intensity starts to wane: it gently drops to 9 at 1:00 PM and gradually decreases to 5 by 3:00 PM. As the afternoon fades into evening, the UV Index dwindles to 3 at 4:00 PM and finally settles at 1 by 5:00 PM, bringing a close to the day's sun exposure risks. As night approaches, the UV Index drops to 0 after 7:00 PM, signifying a safe respite from the sun’s harsh rays.
| 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 | 10 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 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 |
As the seasons change, so do the UV levels, with significant peaks occurring during the summer months. From March to August, the UV Index escalates from a moderate level of 6 in March to an extreme level of 11 in August, indicating a heightened risk for skin damage. April through September represents the high-risk months where the UV Index is categorized as very high to extreme, with burn times decreasing to as little as 10 minutes in August. To safeguard against harmful UV exposure, it is crucial for both visitors and residents to practice sun safety during these months by seeking shade, wearing protective clothing, and applying sunscreen regularly, even on cloudy days. In contrast, the UV Index drops back to a moderate level of 4 in February and 3 during January and December, suggesting lower risk during these winter 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 |
| Yuza | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 11 | 9 | 6 | 4 | 3 |
| 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 |