Last updated: May 3, 2025
Understanding the UV Index is crucial for the residents of Kan'onjicho, Japan, where the impact of sun exposure can significantly affect skin health. With a Cfa climate, this region experiences warm summers and moderate UV radiation throughout the year. By being aware of the UV levels—reaching a peak of 11 around noon—you can take proactive steps to prevent sunburn and long-term skin damage, ensuring safe outdoor enjoyment. With UV indices fluctuating from low to high, it's essential to familiarize yourself with daily values and plan accordingly to protect your skin and overall health.
The UV Index early in the day starts off modest, peaking at 2 by 07:00 and climbing to a moderate 3 by 08:00. By 09:00, it surges to a robust 6, indicating increasing sun intensity. The heat reaches its zenith at 12:00, hitting an impressive 11, showing that midday is the prime time for sun exposure. As the afternoon progresses, the UV Index gradually declines, falling to 10 at 13:00, then to 8 by 14:00. By late afternoon, 15:00 sees it drop to 6, and as the sun sets, the index continues to taper off, descending to 3 by 16:00, and eventually settling at a low 0 by 19:00. It’s a day that underscores the importance of sun protection during peak hours, especially around noon.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 3 | 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 | 0 | low | 45 min |
From January to December, UV Index values exhibit significant seasonal changes, peaking during the summer months. January and December maintain a moderate UV Index of 4, allowing for a burn time of 30 minutes. As spring arrives, March sees a notable increase to 8 (very high), reducing burn time to 15 minutes. The peak UV exposure occurs from May through August, where the index reaches a maximum of 12 (extreme), necessitating a burn time as brief as 10 minutes. September begins a gradual decline, returning to a very high level of 10, while October and November drop to moderate levels at 5. Visitors and residents should exercise caution from March to August, particularly during these high-risk months, by wearing protective clothing, applying sunscreen frequently, and seeking shade to limit UV exposure.
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 |
| Kan'onjicho | 4 | 5 | 8 | 10 | 11 | 11 | 12 | 12 | 10 | 7 | 5 | 4 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |