Last updated: July 2, 2025
In Katori-shi, Japan, awareness of the UV Index is crucial for protecting your skin and overall health. Understanding UV levels can significantly reduce the risk of sunburn and long-term skin damage. With a Cfa climate, Katori-shi experiences varied weather patterns, but the UV exposure can be intense, especially during midday when the index peaks at 11. Being informed about these levels empowers residents and visitors alike to take proactive measures against harmful UV radiation, ensuring a safe and enjoyable time outdoors.
The UV Index (UVI) exhibits a notable pattern throughout the day. Starting at 2 at 7:00 AM, it gradually rises, peaking at 11 by noon and 1:00 PM. This high level of UV exposure indicates that sun protection is essential during these hours. As the afternoon progresses, the UVI begins to dip, dropping to 7 by 2:00 PM and then declining further to 5 by 3:00 PM. By late afternoon, the sunlight's intensity reduces significantly, with the UVI falling to 1 by 5:00 PM and remaining minimal through 6:00 PM and 7:00 PM. This data underscores the importance of taking precautions during peak hours while enjoying the outdoors.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | 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, the UV Index experiences significant seasonal changes, with January and December presenting the lowest levels (UV Index 3) and the summer months of June and July reaching peak levels (UV Index 11), categorized as extreme. April and May also have very high readings (UV Index 9-10), indicating a gradual increase in risk as spring progresses into summer. March, August, and September maintain a high risk for UV exposure (UV Index 7-9). Visitors and residents are advised to take precautions from March through October, especially during the extreme months of June and July, by seeking shade, wearing protective clothing, and applying sunscreen regularly, as burn times decrease significantly to as little as 10 minutes during peak UV periods.
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 |
| Katori-shi | 3 | 5 | 7 | 9 | 10 | 11 | 11 | 10 | 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 |