Last updated: June 2, 2025
Awareness of the UV Index is crucial for residents and visitors in Kariya, Japan, where the climate is characterized by humid subtropical conditions. Understanding UV levels can significantly contribute to sunburn prevention and overall skin health, helping to minimize the risk of long-term damage. With peak UV levels reaching 11 around midday, it’s important to take precautions, especially during the warmer months when daily exposure can lead to increased skin risks. Stay informed about UV exposure to enjoy the beautiful weather while protecting your skin!
The UV Index data reveals a clear pattern in solar exposure throughout the day. Morning rays begin gently, with a maximum of 2 at 07:00, steadily rising to 4 by 08:00. As the sun climbs higher, the index peaks at an impressive 11 at 12:00, indicating a moment of intense UV radiation. Temperatures remain elevated with a 10 at 11:00 and 13:00, before gradually declining to 8 by 14:00. The afternoon light softens, dropping to 6 by 15:00, then continues to retreat as the sun sets—falling to 3 at 16:00, 2 at 17:00, and reaching 1 by 18:00 and 19:00. This data underscores the importance of protecting your skin during the peak hours, especially between 10:00 and 14:00, when the UV Index is at its highest.
| 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 | 11 | extreme | 10 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV index experiences significant fluctuations, indicating varying levels of sun exposure risk. High-risk months are primarily from March to September, where UV indexes peak at 11 or 12, signaling extreme exposure levels and necessitating caution. Residents and visitors should be particularly vigilant during these months, with recommended burn times dropping to as low as 10 minutes in peak summer months. In contrast, the winter months of January, February, November, and December see moderate UV levels (index 4-5), with more manageable burn times of 30 minutes. To ensure safety, it’s advisable for individuals to wear protective clothing, apply sunscreen, and seek shade during peak UV hours, especially from late spring through early fall.
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 |
| 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 |
| Kariya | 4 | 5 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 4 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |