Last updated: May 3, 2025
Understanding the UV Index in Shonai, Japan, is crucial for maintaining skin health and preventing sunburn. As a region with a Cfa climate characterized by warm summers and moderate UV exposure, residents and visitors should be mindful of the fluctuating UV levels throughout the day. With peak values reaching 10 around midday, it’s essential to be aware of these levels to protect your skin from harmful effects, including premature aging and skin cancer. Stay informed and enjoy the sun safely in Shonai!
The UV Index throughout the day showcases a dynamic pattern of solar intensity. Starting with a gentle 2 at 07:00, the index climbs steadily, peaking at a robust 10 by 11:00. This marks the day's critical moment for sun exposure, where protection is essential. As the afternoon unfolds, from 12:00 to 14:00, the index gradually dips from 9 to 6, indicating a shift but still warranting caution. By 15:00, it further eases to 4, and as the sun begins to set, it dwindles to a 1 by 17:00. Finally, by 19:00, the UV Index plummets to 0, signaling a safe period for outdoor activities. Overall, this hourly journey of the UV Index highlights the importance of sun safety during the peak hours.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | 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 | 9 | 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, impacting sun safety for residents and visitors. With moderate exposure levels in January and February (UV Index 3-4), individuals can safely enjoy outdoor activities with a burn time of 30 minutes. As we move into March, the UV Index reaches a high level of 6, reducing burn time to 25 minutes, and continues to escalate through April and May, where it peaks at very high levels of 9, necessitating a burn time of just 15 minutes. The extreme risk months of July and August, with a UV Index of 11, emphasize the need for heightened sun protection, allowing only 10 minutes of unprotected sun exposure. The UV Index decreases again in September to 9, remains at 6 in October, and returns to moderate levels in November and December. To ensure safety, visitors and residents should adopt protective measures—such as sunscreen and clothing—during the high-risk months of April through August, particularly on the most intense days when UV levels peak.
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 |
| Shonai | 3 | 4 | 6 | 9 | 9 | 10 | 11 | 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 |