Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Shirone, Japan, as it plays a key role in protecting your skin from harmful ultraviolet radiation. With peaks reaching 10 during midday hours, being aware of UV levels is essential for preventing sunburn and maintaining long-term skin health. Shirone's Cfa climate brings warm summers and ample sunlight, increasing the risk of UV exposure, especially between 10 AM and 2 PM. By keeping an eye on the UV Index, you can enjoy the sunny days while safeguarding your skin from its damaging effects.
As the day unfolds, the UV Index begins at a mild 2 at 7:00 AM, slowly rising to reach a moderate 4 by 8:00 AM. The intensity climbs steadily, peaking at 10 by 11:00 AM and remaining at this maximum level until 12:00 PM. As the afternoon approaches, the index begins to decline, dropping to 9 at 1:00 PM, and back to 4 by 3:00 PM. By the time the sun sets, the UV Index decreases significantly to 1 at 5:00 PM and just 0 by 7:00 PM, making the early hours the most crucial for sun protection. Remember, while outdoor activities are enticing, being mindful of the UV levels is essential for skin safety!
| 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 | 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 | 2 | low | 45 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV exposure varies significantly, peaking during the summer months. The highest risk for sunburn occurs from April to August, with the UV Index reaching extreme levels of 11 in both July and August, where the burn time is as short as 10 minutes. March marks the transition to higher UV levels, classified as high, and offers a burn time of 25 minutes. As spring progresses into summer, the risk escalates, with the very high category dominating from April through September, emphasizing the need for sun protection. Visitors and residents should take precautionary measures during these high-risk months, including wearing sunscreen, protective clothing, and seeking shade, especially during peak hours. As the year winds down, November and December return to a moderate UV Index (3-4), allowing for more time outdoors, but vigilance is still recommended.
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 |
| Shirone | 3 | 4 | 7 | 9 | 10 | 10 | 11 | 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 |