Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Uki, Japan, where the Cfa climate brings a mix of sunny days and varying UV exposure levels throughout the year. Recognizing UV levels is essential for preventing sunburn, protecting skin health, and reducing the risk of long-term damage. During peak hours, especially between 11:00 AM and 1:00 PM, the UV Index can soar to 12, indicating a high risk of harm from unprotected sun exposure. By staying informed about these UV levels, you can enjoy the beautiful weather Uki has to offer while keeping your skin safe and healthy.
The UV Index throughout the day showcases a dynamic shift in sun intensity, peaking at 12 around noon. Beginning with a gentle 2 at 7:00 AM, the index steadily increases, hitting 11 by 11:00 AM as the sun climbs higher. By 12:00 PM, the sun reaches its zenith at 12, marking the highest UV exposure, making sun safety a priority. As the afternoon progresses, from 1:00 PM to 3:00 PM, the UV Index gradually decreases to 9 by 2:00 PM and 7 by 3:00 PM. The day winds down with a notable drop in intensity, returning to a mild 1 by 6:00 PM, emphasizing that the safest time to enjoy the sun is before noon or after 4:00 PM.
| 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 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | 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, UV Index levels fluctuate, indicating varying sun exposure risks. High-risk months are predominantly from March to September, where the UV Index frequently reaches extreme levels (10-13), with May to August being critically important, showing consistent values of 12 or higher. In March, the UV Index rises sharply to 9, followed by April and May with values of 10 and 12 respectively. It's vital for residents and visitors to understand that during this period, burn times decrease significantly to just 10 minutes, necessitating proactive sun safety measures such as wearing sunscreen, protective clothing, and seeking shade, especially between 10 AM and 4 PM. As the year progresses into the fall, UV levels gradually decline, but caution is still advised in October when the index remains high at 8. In winter, UV exposure returns to moderate levels, allowing for longer burn times in January and December, yet awareness and prevention remain essential year-round.
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 |
| Osaka UVI | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 11 | 10 | 7 | 5 | 3 |
| Uki | 5 | 6 | 9 | 10 | 12 | 12 | 13 | 13 | 11 | 8 | 6 | 4 |