Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Shimabara, Japan, where the subtropical climate can lead to significant sun exposure throughout the year. Being aware of UV levels helps prevent sunburn and reduces the long-term risks of skin damage, making it essential for everyone who enjoys the outdoor beauty of this region. With UV Index readings peaking at 11 around midday—indicative of very high risk—Shimabara's warm climate calls for vigilance during the sunnier months. By monitoring these levels, you can effectively safeguard your skin while embracing all that this scenic locale has to offer.
As the sun rises, the UV Index starts at a mild 1 at 7:00 AM, perfect for early risers. By 8:00 AM, it increases to a moderate 3, hinting at the day ahead. Things heat up quickly, with the index peaking at an intense 11 around 12:00 PM, a reminder that sun protection is essential during midday. The UV levels maintain a strong presence, remaining at 10 at 1:00 PM before gradually tapering off to 9 by 2:00 PM. As the afternoon wanes, the UV Index drops to a cozy 6 at 3:00 PM and further descends to 4 by 4:00 PM. By the evening, the sun loses its intensity, with the index falling to 2 at 5:00 PM, and settling back to a safe 1 from 6:00 PM onward. This daily cycle underscores the importance of being sun smart, especially during peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | 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 | 9 | 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, 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 |