Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Rifu, Japan, as it serves as a key indicator of the sun's intensity and the potential risk for skin damage. Being aware of UV levels helps individuals make informed decisions to protect their skin from harmful effects, including sunburn and long-term skin health issues. In Rifu's Cfa climate, characterized by warm summers and ample sunshine, the UV exposure risks can escalate quickly, particularly during peak hours when the index reaches its maximum of 11 around noon. By staying informed about the UV Index, you can enjoy the warm Japanese sun while keeping your skin safe and healthy.
As the day unfolds, the UV Index climbs steadily, peaking at 11 between 11:00 and 12:00, signaling a strong need for sun protection during these hours. Starting from a mild 3 at 07:00, the intensity rapidly rises, reaching a noticeable 5 by 08:00 and soaring to 9 by 10:00. However, the sun's intensity begins to wane in the afternoon, dropping to 7 and then 5 from 13:00 to 15:00. By 16:00, the UV Index retreats to 3, and as evening sets in, it diminishes further to 1 by 17:00 and falls to 0 by 19:00. It's crucial to stay vigilant during those peak hours to enjoy the sun 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 | 11 | extreme | 10 min |
| 12:00 | 11 | extreme | 10 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 does the UV Index, impacting both visitors and residents. From January to February, the UV Index remains at a moderate level (3-4), allowing for 30 minutes of sun exposure without significant risk. However, as spring approaches in March, the index climbs to high (7), reducing safe exposure to 25 minutes. The peak UV Index occurs during summer months, notably in July and August, where it reaches an extreme level (11) with a mere 10 minutes of safe exposure. September sees a decline to very high (9), while October returns to high (6) conditions, each allowing for a bit more time in the sun—25 minutes and 15 minutes respectively. From November to December, the UV risks lower again to moderate (3-4), allowing for 30 minutes. Visitors and residents should be especially cautious from March through September, particularly during peak summer months, by applying sunscreen, wearing protective clothing, and limiting sun exposure to mitigate the risk of UV-related health issues.
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 |
| Rifu | 3 | 4 | 7 | 8 | 10 | 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 |