Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Iwaizumi, Japan, as it serves as an essential guide for sun safety and skin health. With peak UV levels reaching up to 10 during midday hours, being aware of these fluctuations can significantly impact your ability to prevent sunburn and long-term skin damage. Situated in a Dfb climate zone, Iwaizumi experiences notable seasonal variations that influence UV exposure, making it vital to stay informed. Protecting your skin from harmful rays not only promotes immediate well-being but fosters overall health in the long run.
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 |
Throughout the year, the UV Index experiences significant fluctuations, peaking during the summer months. January and December show a moderate UV Index of 3, allowing for 30 minutes of sun exposure without risk of burning. As the seasons progress into February and March, the UV Index rises to 4 and 6 respectively, marking the start of the high-risk months. The situation escalates in April and May, where the UV Index reaches 9, categorized as very high, significantly reducing safe exposure time to just 15 minutes. The intensity peaks in June and August with an extreme UV Index of 11, necessitating caution, as even 10 minutes of sun can lead to burns. July and September follow closely with a very high index of 10 and 9 respectively. As autumn approaches, the UV levels drop again to 6 in October, and gradually return to moderate levels in November and December. Visitors and residents are advised to take precautions, especially during the high and extreme months, by using sunscreen, wearing protective clothing, and seeking shade during peak sun hours to safeguard against harmful UV exposure.
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 |
| Iwaizumi | 3 | 4 | 6 | 9 | 9 | 11 | 10 | 11 | 9 | 6 | 4 | 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 |