Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Honjo, Japan, where the sun frequently shines brightly throughout the year. With the region's Cfa climate, UV levels can soar, particularly in the midday hours, reaching a peak of 11 between 12:00 PM and 1:00 PM. Awareness of these UV levels is vital for sunburn prevention and maintaining long-term skin health. By monitoring the UV Index, you can effectively plan your outdoor activities and safeguard yourself against the harmful effects of excessive sun exposure, ensuring a healthy and enjoyable time in this beautiful city.
As the day unfolds, the UV Index begins to climb, starting at a mild 2 by 07:00. By 08:00, it ascends to a moderate 5, indicating that sun protection becomes essential. The intensity peaks at 11 between 11:00 and 12:00, marking the hours when solar radiation is most potent. Following this peak, the index gradually declines; it drops to 10 at 13:00, before descending to 7 by 14:00. The afternoon sees a further decrease, with readings of 5 at 15:00 and 3 at 16:00—perfect for those wishing to enjoy the sun while still being cautious. By 17:00, the index falls to a mild 1, and as the day winds down, it reaches 0 by 19:00, signaling a retreat from the sun's harmful rays. It’s crucial to stay informed and protect your skin during peak UV hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 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 | 10 | 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 |
Throughout the year, UV levels demonstrate significant seasonal variations, with high-risk months typically occurring from March through August. During this period, the UV Index peaks at 11 in June, July, and August, marking it as an extreme risk category with a burn time of just 10 minutes. In contrast, the lowest UV Index readings, categorized as moderate, occur in January, February, November, and December, allowing for 30-minute exposure without immediate risk of skin damage. Visitors and residents should prioritize sun safety measures, particularly in the high-risk months—using sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize potential harm from intense UV radiation.
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 |
| Honjo | 3 | 5 | 8 | 9 | 10 | 11 | 11 | 11 | 9 | 7 | 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 |