Last updated: May 3, 2025
Understanding the UV Index in Ishioka, Japan is crucial for safeguarding skin health and preventing sunburn, especially during the peak summer months. With a humid subtropical climate (Cfa) that often sees high UV levels, knowing when the sun's rays are strongest can help residents and visitors plan their outdoor activities wisely. The UV Index can reach a maximum of 10 around noon, indicating an elevated risk of harm from unprotected sun exposure. By staying informed about local UV levels, you can enjoy the beautiful warm days while taking the necessary precautions to protect your skin.
In the morning, the UV Index starts off relatively low, peaking at 3 by 7 AM. As the day progresses, it steadily climbs, reaching a notable high of 10 at both 11 AM and 12 PM—this is the time to be cautious! The index then begins to dip and falls back to a moderate level of 4 by 3 PM, before dwindling to 1 by 5 PM, and finally settling at 0 by 7 PM. For those enjoying outdoor activities, it’s essential to stay sun-smart during the mid-day hours when UV radiation is at its peak!
| 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 | 10 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | 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 |
The UV Index exhibits notable seasonal changes throughout the year, with high-risk months primarily occurring from March to September. March marks the shift to a high category (UV Index 7), while April and May escalate to very high (UV Index 9-10), culminating in extreme exposure levels during June and July (UV Index 11). As summer transitions to fall, the UV levels gradually decline, dipping to moderate levels by November and December. Visitors and residents should take necessary precautions, especially during the peak months of June and July, where the burn time is drastically reduced to just 10 minutes. It is advisable to wear protective clothing, apply sunscreen frequently, and seek shade during these high-risk times to minimize skin damage and health risks.
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 |
| Ishioka | 3 | 5 | 7 | 9 | 10 | 11 | 11 | 10 | 9 | 6 | 5 | 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 |