Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Hiratacho, Japan, where the subtropical Cfa climate invites ample sunlight throughout the year. With UV levels peaking at a high of 11 during midday, awareness of these fluctuations fosters essential sunburn prevention and promotes long-term skin health. By grasping the significance of UV exposure risks, particularly during those intense hours, you can enjoy Hiratacho's sunny days while protecting your skin from harmful radiation. Stay informed and safeguard your health under the Japanese sun!
The UV Index paints a vivid picture of the sun’s strength throughout the day. Starting at a modest 2 at 07:00, the index gradually climbs as the sun ascends, reaching 4 by 08:00. By 09:00, it spikes to 6, and before long, it peaks at an impressive 11 at 12:00, marking the most intense exposure. The afternoon starts to cool slightly, with the index dropping to 10 by 13:00 and then tapering off through 8 at 14:00, 6 at 15:00, and back to 4 at 16:00. As the sun begins its descent, the UV Index falls to 2 by 17:00, lingering at 1 through the evening hours, creating a gentle reminder to enjoy the sun but also to stay mindful of its intensity during peak hours.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 4 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index shows significant seasonal changes, with elevated levels during the warmer months from March to September. High-risk months for UV exposure include April to August, where the index peaks at 10-12, indicating very high to extreme exposure levels and a drastically reduced burn time of only 10-15 minutes. During this period, it is crucial for both visitors and residents to take precautions by seeking shade, wearing protective clothing, and applying sunscreen regularly to minimize the risk of skin damage. Conversely, the winter months of January, February, November, and December see a moderate UV index, allowing for a safer level of outdoor activity with a longer burn time of 30 minutes.
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 |
| 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 |
| Hiratacho | 3 | 5 | 7 | 10 | 10 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |
| 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 |