Last updated: July 2, 2025
Understanding the UV Index is essential for residents and visitors in Ishikari, Japan, where the climate can bring varying levels of sun exposure. With a climate classified as Dfb, characterized by warm summers, it's vital to be aware of the potential risks associated with UV radiation, especially during peak hours when levels can reach as high as 9 around midday. Knowing the UV levels is crucial for preventing sunburn and maintaining overall skin health throughout the year. Staying informed can help you take proactive steps to protect yourself and enjoy the sunshine safely, especially when the risk of UV exposure tends to increase significantly during the summer months.
The UV Index steadily climbs throughout the morning, peaking at 9 between 11:00 and 12:00, indicating intense sun exposure that requires caution. As the day progresses, the index begins to decline, dropping to 7 by 14:00 and further decreasing to 5 by 15:00. By late afternoon, the UV levels drop significantly, reaching 1 by 16:00 and remaining low until sunset. It's crucial to stay protected during the midday hours when the UV Index is at its highest; wearing sunscreen and protective clothing is highly recommended to enjoy safe outdoor activities!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 9 | very high | 15 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 8 | 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 | 1 | low | 45 min |
Throughout the year, the UV Index experiences notable seasonal changes, indicating varying levels of sun exposure risk. The high-risk months typically occur from May to August, when the UV Index reaches very high levels (9-10), warranting caution as the burn time decreases to just 15 minutes. In contrast, the winter months of December and January present a much lower risk, with UV indexes of 2 and burn times extending to 45 minutes. Visitors and residents are advised to take appropriate precautions during the high-risk months, such as wearing protective clothing, applying broad-spectrum sunscreen, and seeking shade during peak sun hours to minimize potential skin damage. For the moderate months of February, April, October, and November, it’s important to remain aware of UV exposure and adjust outdoor activities accordingly.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ishikari | 2 | 3 | 6 | 7 | 9 | 9 | 9 | 10 | 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 |