Last updated: May 3, 2025
Understanding the UV Index is crucial for the residents of Sekimachi, Japan, where the unique Cfa climate can lead to varying levels of ultraviolet radiation throughout the day. Monitoring UV levels is not just about avoiding sunburn; it’s essential for maintaining skin health and reducing the risk of long-term damage. With peak UV exposure reaching an intensity of 11 around midday, it's important for locals and visitors alike to stay informed and take protective measures. Be vigilant during those sun-kissed hours, particularly between 10 AM and 2 PM, when the sun's rays can pose significant risks, ensuring you enjoy the beautiful weather while safeguarding your skin.
The UV Index throughout the day presents a dynamic picture of sun exposure. As early as 7:00 AM, the index starts at a mild 2, ramping up to a moderate 4 by 8:00 AM. The sun's intensity peaks around 11:00 AM and 12:00 PM with a striking 11, marking the height of caution for outdoor activities. As we move into the afternoon, the index gradually declines, dropping to 8 by 2:00 PM and further to 5 by 3:00 PM. The evening brings relief, with the UV Index decreasing to a 1 by 5:00 PM and finally hitting 0 by 7:00 PM. It’s clear that the midday hours pose the greatest risk, so sun safety measures are essential during those peak times.
| 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 | 8 | very high | 15 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 exposure varies significantly, peaking during the summer months. High-risk months for UV exposure are from March to August, when the UV Index reaches its maximum levels of 10 to 11 and the burn time is as brief as 10 minutes. Notably, May through August features extreme exposure, requiring diligent sun protection practices. As the year transitions into fall, September to November sees a decrease in UV levels, with October still posing a moderate risk. To ensure safety, visitors and residents are advised to wear protective clothing, use sunscreen, and seek shade during the peak sun hours, especially from late spring through summer when the threat of sunburn is greatest.
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 |
| Sekimachi | 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 |