Last updated: June 2, 2025
In Itoigawa, Japan, being aware of the UV Index is crucial for protecting your skin while enjoying the outdoors. Understanding UV levels helps prevent sunburn and promotes long-term skin health, especially in a region known for its Cfa climate, which can lead to intense sun exposure during peak hours. With UV Index values peaking at 11 around midday, it’s vital for residents and visitors alike to take precautions and stay informed to enjoy everything this beautiful area has to offer safely.
The UV Index readings throughout the day reveal a dramatic rise in sun intensity as the morning unfolds. Starting at 2 at 07:00, the index climbs steadily, peaking at a scorching 11 by noon and remaining high until around 13:00. As the afternoon progresses, the UV Index gently declines, dropping to 5 by 15:00 and further descending to 1 by the evening hours. This pattern highlights the importance of sun protection during midday, as the intense solar radiation can pose health risks. Stay safe and enjoy the sun wisely!
| 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 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | 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 |
| Itoigawa | 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 |