Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Custoias, Portugal, where sunny days can lead to increased exposure to harmful ultraviolet radiation. With a climate characterized by mild, wet winters and warm, dry summers, the UV levels here can vary significantly throughout the day, peaking at a high of 10 between 1:00 PM and 2:00 PM. Being aware of these levels is essential for preventing sunburns and promoting long-term skin health, as even a short period of intense UV exposure can lead to significant skin damage. Stay informed and protect yourself while enjoying the beautiful outdoors!
The UV Index for the day showcases a striking ascent in intensity, peaking during the afternoon hours. Starting from a low of 1 at 07:00 and 08:00, the index swiftly climbs to reach 3 by 09:00. By 10:00, it escalates to a moderate 5, but the real surge occurs between 11:00 and 14:00, hitting a maximum of 10—indicating a high risk of harm from unprotected sun exposure. As the day progresses, the UV Index gradually drops, retracting to 4 by 17:00 and further declining to 1 by 19:00. It's crucial to stay protected during those peak hours!
| 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 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 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 |
| Custoias | 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 |