Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Watari, Japan, especially given the region's Cfa climate, which can lead to significant sun exposure. Being aware of the UV levels not only helps in preventing painful sunburns but also plays a vital role in maintaining long-term skin health. With UV Index levels peaking at 11 during midday, typically from 11:00 AM to 1:00 PM, it's essential for everyone—locals and visitors alike—to take protective measures against harmful UV radiation. Whether you're enjoying outdoor activities or simply soaking in the sun, staying informed about the UV Index can make a significant difference in your overall well-being.
As the day unfolds, the UV Index climbs steadily, peaking at 11 between 11:00 and 12:00, signaling a strong need for sun protection during these hours. Starting from a mild 3 at 07:00, the intensity rapidly rises, reaching a noticeable 5 by 08:00 and soaring to 9 by 10:00. However, the sun's intensity begins to wane in the afternoon, dropping to 7 and then 5 from 13:00 to 15:00. By 16:00, the UV Index retreats to 3, and as evening sets in, it diminishes further to 1 by 17:00 and falls to 0 by 19:00. It's crucial to stay vigilant during those peak hours to enjoy the sun safely!
| 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 | 11 | extreme | 10 min |
| 12:00 | 11 | extreme | 10 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 |
As the seasons change, so does the UV Index, significantly impacting sun exposure and the risk of skin damage. From January to February, the UV Index is moderate (3-4) with a longer burn time of 30 minutes. However, as we transition into March and April, the UV Index rises sharply to high (7) and very high (8) respectively, with burn times decreasing to just 25 and 15 minutes. The peak UV intensity occurs during the summer months of July and August when the Index reaches an extreme level of 11, with a mere 10 minutes for potential sunburn. Visitors and residents should be particularly cautious from March through September, the high-risk months for UV exposure, and take proactive measures such as applying sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize skin damage. As the year concludes, the UV levels drop again in October to moderate levels in November and December, providing a respite from intense sun 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 |
| Watari | 3 | 4 | 7 | 8 | 10 | 10 | 11 | 10 | 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 |