Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors of Yamada, Japan, where the climate typically features mild summers but can still pose significant risks for sun exposure. With UV levels peaking at an intensity of 10 around noon, awareness of these fluctuations is vital for preventing sunburn and preserving long-term skin health. Knowing when the UV Index is at its highest, especially during the sunnier hours from 10:00 AM to 1:00 PM, can help you make informed decisions about sun protection and outdoor activities, allowing you to enjoy Yamada's beautiful scenery while staying safe.
The hourly UV Index paints a clear picture of the day's intensity from morning to evening. Starting at a mild 3 at 7:00 AM, the day warms up quickly, peaking at a robust 10 between 11:00 AM and 12:00 PM—the perfect time to seek shelter or apply sunscreen. After that fleeting high, the UV Index gradually declines, dropping to 4 by 3:00 PM and further diminishing to 1 by 5:00 PM. As the sun sets, the UV levels plummet to a safe 0 by 7:00 PM. This data underscores the importance of protecting your skin during peak hours, especially when the sun is at its strongest.
| 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 | 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, which indicates the strength of ultraviolet radiation. January starts with a low UV Index of 2, increasing gradually to a moderate 4 in February. By March, the Index rises to 6 (high), and April and May see very high levels, peaking at 9 in May. The summer months of June and August experience extreme UV levels of 11, while July remains very high at 10. As summer fades into fall, September experiences a decline to 9, followed by October’s high level of 6. The year closes with November and December at moderate levels of 4 and 3, respectively. Visitors and residents alike should take precaution during the high-risk months of April through August, where burn times are significantly reduced. To protect your skin, it’s advisable to wear sunscreen, seek shade, and wear protective clothing, especially during peak UV hours.
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 |
| Yamada | 2 | 4 | 6 | 8 | 9 | 11 | 10 | 11 | 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 |