Last updated: May 3, 2025
Understanding the UV Index in Iwamizawa, Japan is crucial for protecting your skin and overall health. With maximum UV levels peaking at 8 during the late morning to early afternoon, it’s essential to be aware of potential sunburn risks and long-term skin damage. Iwamizawa's Dfb climate brings distinct seasonal variations, but summer days can lead to high UV exposure, making it vital to know how to stay safe while enjoying the outdoors. By keeping an eye on local UV readings, you can take proactive steps to enjoy the sun without compromising your skin health.
The UV Index presents a compelling picture of solar intensity throughout the day. Early risers will notice a gentle start, with maximum values of 3 at 07:00. As the sun climbs higher, the index peaks at 8 between 10:00 and 12:00, indicating strong sun exposure. This is the best time to take precautions, such as applying sunscreen and wearing protective clothing. The intensity then gradually declines, dropping to 6 by 14:00 and tapering off further to 1 by 17:00. By evening, the UV Index hits 0 at 19:00, offering a safe reprieve as the day winds down. Remember, planning your outdoor activities around these insights can ensure you enjoy the sun while staying safe!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 7 | high | 25 min |
| 14:00 | 6 | 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 |
The UV Index shows a clear seasonal variation, with high-risk months from March to September, where values peak at 10 in August. January and December experience low exposure with a UV Index of 2, while February and November have moderate exposure with an index of 3. During April and May, the UV Index rises significantly, reaching very high levels of 8 and 9, meaning a burn time of just 15 minutes is recommended during peak intensity months. Visitors and residents should take precautions from March through September, especially midday, to protect their skin, including wearing sunscreen, protective clothing, and seeking shade. As UV levels drop in the fall and winter, there is less risk, but some protection is still advisable in February and October.
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 |
| Iwamizawa | 2 | 3 | 6 | 7 | 8 | 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 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |