Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Shiranuka, Japan, where the properties of its Dfb climate can lead to significant ultraviolet exposure. With UV levels peaking at 10 around noon, awareness is key to preventing sunburn and protecting skin health. By monitoring these fluctuations throughout the day, you can make informed decisions about sun protection, ensuring you enjoy outdoor activities while minimizing risks. With Shiranuka's unique climate, knowing the UV Index helps safeguard your well-being under the sun.
As the sun rises, the UV Index steadily climbs, peaking at an impressive 10 between 11:00 and 12:00, signaling intense solar exposure. Starting at a mild 3 at 07:00, it quickly ramps up, reaching 7 by 09:00 and hitting 9 by 10:00. The intensity remains strong until 14:00, where it begins to taper off to 6 and then drops further to 4 and 2 in the late afternoon. As evening approaches, the UV Index dwindles to 1 by 17:00 and finally falls to 0 after 19:00. Stay protected during the peak hours, especially between 11:00 and 14:00, to enjoy the sunny day safely!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 5 | 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 | 8 | very high | 15 min |
| 14:00 | 6 | 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 |
Throughout the year, the UV Index demonstrates significant seasonal variation, with particularly high-risk months occurring from April to September. During this period, the UV Index frequently reaches levels categorized as very high, peaking at 10 in June and July. This translates to a dangerously short burn time of just 15 minutes, emphasizing the importance of sun protection, including sunscreen, hats, and protective clothing. As the year progresses into October and November, the UV Index decreases to more moderate levels, allowing for greater exposure times of 30 minutes without immediate risk of skin damage. Visitors and residents are advised to remain vigilant during peak UV months, seeking shade and reapplying sunscreen as necessary to safeguard their skin health.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Shiranuka | 2 | 3 | 5 | 8 | 8 | 10 | 10 | 9 | 8 | 5 | 3 | 2 |
| 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 |