Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Katagami, Japan, where the subtropical Cfa climate brings a mix of sunny days and variable weather. Monitoring UV levels helps in preventing sunburn and promoting better skin health, as even moderate exposure can lead to harmful effects over time. With peak UV Index readings soaring to 10 around midday, it's essential to be aware of your sun exposure, particularly during the summer months when the risk of skin damage is elevated. Stay informed and protect your skin while enjoying the beautiful outdoors in Katagami!
During the day, the UV Index experiences a dynamic shift, peaking in the late morning. Starting at 3 at 07:00, it escalates to reach a high of 10 by 11:00 and remains there until 12:00. As afternoon approaches, the index gradually declines, dropping back to 9 by 13:00, then to 7 at 14:00. By the mid to late afternoon, it continues its descent, falling to 5 at 15:00 and further down to 3 by 16:00. In the evening, the index diminishes significantly, plummeting to 1 at both 17:00 and 18:00, and finally reaching 0 by 19:00. This pattern highlights the importance of sun protection during the peak hours of 10:00 to 12:00 when the UV radiation is most intense.
| 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 | 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 |
As the seasons change, so do the UV index levels and associated risks for skin damage. During the winter months of January to February, the UV index remains moderate (3-4), allowing for a 30-minute burn time. However, starting in March, the UV index escalates to high (6), indicating the need for increased sun protection. The high-risk months peak from April to August, with the UV index reaching very high (8-10) and even extreme levels (11) in August, where burn times drop to just 10 minutes. September sees a decline to very high (9), while October returns to high levels (6) with a longer burn time of 25 minutes. As winter returns in November and December, the sun's strength diminishes, with indexes dropping to moderate and low (4 and 2), leading to safer burn times of 30 and 45 minutes, respectively. It is crucial for visitors and residents to use sun protection consistently during high-risk months and limit direct sun exposure, especially during midday hours.
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 |
| Katagami | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 11 | 9 | 6 | 4 | 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 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |