Last updated: July 2, 2025
In Muroran, Japan, understanding the UV Index is crucial for safeguarding your skin and maintaining overall health. As one of the premier port cities in Hokkaido, Muroran experiences a climate classified as Dfb, characterized by cold winters and warm summers. With UV levels reaching a peak of 10 around noon, it's essential to be aware of daily UV exposure to prevent sunburn and long-term skin damage. By monitoring the UV Index, residents and visitors alike can take proactive measures to protect themselves during the sun's peak hours, ensuring a safe and enjoyable experience in this beautiful coastal city.
As the day unfolds, the UV Index rises dramatically, peaking at 10 by 12:00 PM, indicating a high risk of harm from unprotected sun exposure. From a moderate 4 at 08:00 AM, it steadily climbs, reaching 9 by 11:00 AM, urging early sun seekers to take precautions. After the midday peak, a gradual decline begins, dropping to 7 at 02:00 PM and further to 5 by 03:00 PM. The UV intensity continues to fade throughout the afternoon, settling to a minimal 1 by 05:00 PM, signaling a safer time for outdoor activities. As the day transitions, the sun’s aggressive rays soften, allowing you to enjoy the evening while remaining mindful of skin protection earlier in the day.
| 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 | 9 | 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 | 1 | low | 45 min |
Throughout the year, the UV Index demonstrates significant seasonal variations that highlight the importance of sun safety. From January to March, the UV levels are generally low to moderate, with burn times ranging from 30 to 45 minutes. However, April marks the start of high-risk months, peaking with May and August, where the UV Index reaches a very high level of 9 and 10, drastically reducing safe sun exposure to just 15 minutes. Following these months, September and October maintain elevated UV levels before returning to more moderate levels in November and December. Residents and visitors are strongly advised to take precautions during high-risk months (April through September) by wearing sunscreen, protective clothing, and seeking shade during peak sun hours to minimize the risk of skin damage.
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 |
| Muroran | 2 | 3 | 5 | 7 | 9 | 10 | 9 | 10 | 8 | 6 | 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 |