Last updated: July 2, 2025
In Ujiie, Japan, awareness of the UV Index is essential for maintaining skin health and preventing sunburn. With the city experiencing a Cfa climate, the sun can be quite intense, especially during peak hours when UV levels soar to a maximum of 10 around noon. Understanding these variations in UV exposure not only helps residents and visitors protect their skin but also promotes long-term health. Whether you're enjoying outdoor activities or simply soaking up the sun, staying informed about the UV Index can make all the difference in keeping your skin safe and healthy.
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 |
The seasonal UV variations indicate a significant increase in UV exposure from winter to summer, with high-risk months emerging from April through August. During this period, the UV Index peaks at 11 (extreme), particularly in June, July, and August, where the burn time drops to just 10 minutes. Visitors and residents are advised to take precautionary measures during these months, such as seeking shade, wearing protective clothing, and applying sunscreen frequently. As the UV levels decrease in the fall and winter months, with indices dropping to 3 in January and December, the risk of sunburn diminishes. However, maintaining sun safety practices year-round remains essential for health and well-being.
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 |
| Ujiie | 3 | 5 | 7 | 9 | 10 | 11 | 11 | 11 | 9 | 7 | 5 | 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 |