Last updated: August 1, 2025
Understanding the UV Index in Shimabara, Japan is essential for safeguarding your skin against harmful ultraviolet radiation. With the region's humid subtropical climate (Cfa), residents and visitors alike must be vigilant as UV levels can peak dramatically, especially during midday hours. Knowledge of these levels is crucial for effective sunburn prevention and long-term skin health, as exposure can lead to serious dermatological issues. With values reaching a maximum of 12 between 12:00 and 13:00, Shimabara's UV exposure poses significant risks, making it vital to stay informed and take appropriate precautions when enjoying the outdoors.
During the morning hours, the UV Index starts off low at 1 at 7:00 AM, indicating minimal risk of harm from unprotected sun exposure. As the day progresses, the intensity ramps up, peaking at 12 around 12:00 PM and 1:00 PM, suggesting a high risk for harm, especially for those spending extended periods outdoors. Post-peak, the index gradually declines, dropping to 7 at 3:00 PM and further down to 1 by 7:00 PM, which indicates a return to minimal risk as the sun sets. For sun enthusiasts, midday offers the most intense UV radiation, making sun protection essential during those hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 5 | moderate | 30 min |
| 10:00 | 8 | very high | 15 min |
| 11:00 | 10 | very high | 15 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, seasonal changes in UV exposure highlight periods of heightened risk for residents and visitors. From January to February, the UV Index rises from 4 (moderate) to 6 (high), reducing safe exposure time to 25 minutes. Significant increases occur in March, reaching 8 (very high), and peaking during the summer months of April to August at 11-12 (extreme), where only 10 minutes of unprotected exposure is advisable. The risk, while still present, decreases again in September and returns to high levels in October and November with a UV Index of 6-7, allowing for 25 minutes of safe exposure. As such, it is crucial for visitors and residents to remain vigilant, especially during the summer, taking precautions like wearing sunscreen, protective clothing, and seeking shade during peak hours to mitigate the risk of UV-related health issues.
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 |
| Shimabara | 4 | 6 | 8 | 11 | 11 | 11 | 12 | 12 | 11 | 7 | 6 | 4 |