Last updated: May 3, 2025
Understanding the UV Index is essential for residents and visitors of Castro Daire, Portugal, where the sun can be both inviting and intense. With a climate characterized by warm summers and mild winters, awareness of UV levels is crucial for preventing sunburn and maintaining skin health. During peak hours, especially around noon when the UV Index can reach 10, the risk of skin damage significantly increases. By staying informed about these daily fluctuations, you can enjoy the beautiful outdoor scenery of Castro Daire while protecting yourself from harmful ultraviolet radiation.
The UV Index throughout the day presents a clear narrative of rising intensity, peaking in the afternoon. Starting at 1 by 07:00, the UV levels gradually ascend, reaching 5 by 10:00. By 11:00, the index climbs to 7, and it soars to a striking 10 at 13:00—the optimal time for sun precautions. The intensity slightly wanes thereafter, dropping to 9 at 14:00 and continuing down to 4 by 17:00. As evening approaches, the UV Index dwindles to 1 by 19:00, signaling a return to safer levels. This data underscores the importance of sun safety measures during peak hours, particularly between 11:00 and 14:00.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index shows a clear seasonal pattern, with increasing intensity from January to June and a gradual decline thereafter. March marks the transition to high risk, followed by extremely high levels in June (UV Index 11). April and May also present very high values (UV Index 9), making them critical months for sun exposure. From June to September, the UV Index remains predominantly in the very high category, indicating a heightened risk for sunburn and skin damage. Residents and visitors should take precautions, especially during April to September, by wearing protective clothing, applying sunscreen, and limiting time in direct sunlight, particularly during peak hours. As October and November roll in, UV levels decrease significantly, providing some relief, although it's still advisable to stay cautious with moderate UV levels in these months.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Braga UVI | 2 | 4 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 6 | 4 | 2 |
| Porto UVI | 2 | 4 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 6 | 4 | 2 |
| Castro Daire | 3 | 4 | 6 | 9 | 9 | 11 | 10 | 9 | 8 | 6 | 4 | 2 |
| Amadora UVI | 3 | 5 | 6 | 9 | 10 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| Lisbon UVI | 3 | 5 | 6 | 9 | 10 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| Setubal UVI | 3 | 5 | 6 | 9 | 10 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |