Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Iwaki, Japan, as it plays a vital role in protecting skin health and preventing sunburn. With its Cfa climate, Iwaki experiences varying UV levels throughout the day, peaking at midday with values reaching 10 on the index. This elevated exposure underscores the importance of being aware of UV levels to take proactive measures against harmful rays. Whether you’re enjoying outdoor activities or simply relaxing in the sun, knowing the UV Index helps you make informed decisions to safeguard your skin and overall wellness.
In the morning, the UV Index starts off relatively low, peaking at 3 by 7 AM. As the day progresses, it steadily climbs, reaching a notable high of 10 at both 11 AM and 12 PM—this is the time to be cautious! The index then begins to dip and falls back to a moderate level of 4 by 3 PM, before dwindling to 1 by 5 PM, and finally settling at 0 by 7 PM. For those enjoying outdoor activities, it’s essential to stay sun-smart during the mid-day hours when UV radiation is at its peak!
| 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 | 4 | moderate | 30 min |
| 16:00 | 2 | low | 45 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV Index values experience significant seasonal changes, indicating varying levels of sun exposure risk. January and December have moderate UV Indexes (3), suggesting a safer exposure time of 30 minutes. As we move into February and November, the UV Index rises to 5, still moderate, but caution is warranted with a similar burn time. From March to October, the UV Index escalates, reaching its peak between July and August at an extreme level of 11, where only a mere 10 minutes of exposure can lead to burns. April and May also present very high risk with indexes of 9 and 10, respectively, offering 15 minutes of allowed exposure. The fall months, including September with a UV Index of 9, still require vigilance. Visitors and residents are urged to take necessary precautions during high-risk months—especially from March through August—to protect their skin, such as seeking shade, wearing protective clothing, and applying broad-spectrum sunscreen regularly.
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 |
| Iwaki | 3 | 5 | 7 | 9 | 10 | 10 | 11 | 11 | 9 | 6 | 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 |