Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of Shiso, Japan, where sunny days are frequent in its temperate Cfa climate. With UV levels peaking at 11 around midday, awareness of these indices is essential to ensure proper sunburn prevention and to protect your skin health. By keeping an eye on the UV Index, you can enjoy outdoor activities while minimizing the risks associated with excessive sun exposure, such as skin cancer and premature aging. Whether you're planning a day at the park or simply taking a stroll, knowing the UV levels can help you stay safe under the sun in beautiful Shiso.
As the day begins, the UV Index starts off low at 2 by 7:00 AM, perfect for early morning activities. However, things heat up as the sun rises higher, reaching 3 by 8:00 AM, and peaking at an impressive 11 around noon. This midday mark, particularly at 12:00 PM, signals the need for sun protection as UV levels can cause harm with prolonged exposure. The intensity begins to wane after 1:00 PM, dropping to 10, then gently descending to 5 by 3:00 PM. As evening approaches, the UV radiation diminishes further, hitting 1 by 6:00 PM and finally tapering off to 0 by 7:00 PM. Keep in mind that the sun’s strength is at its highest during midday, making it crucial to take precautions if you plan to be outdoors!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | 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 | 5 | moderate | 30 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 2 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, the UV Index experiences significant fluctuations, with the highest risk months typically from April to August, when values peak at 11-12 and fall into the extreme exposure category. Notably, July and August record the highest UV levels, necessitating diligent sun protection strategies. In contrast, the lower risk period spans from November to February, where the UV Index varies between 3 and 6, indicating moderate to high exposure. Visitors and residents are advised to take extra precautions during the high-risk months by seeking shade, wearing protective clothing, and applying sunscreen regularly 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 |
| 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 |
| Shiso | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 12 | 10 | 7 | 5 | 3 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |