Last updated: July 2, 2025
Staying informed about the UV Index is crucial for residents and visitors in Sao Martinho do Porto, Portugal, where the Mediterranean climate brings warm summers and increased sun exposure. Understanding UV levels helps you protect your skin from dangerous sunburns and long-term health issues related to sun damage. With midday readings often peaking at a high of 10, the risks of harmful exposure are significant during the summer months. By keeping an eye on the UV Index, you can enjoy the beautiful sandy beaches and stunning coastal views while safeguarding your skin and overall health.
The UV Index throughout the day presents a dynamic portrait of solar intensity. Early morning hours from 7:00 to 8:00 maintain a gentle glow with a consistent level of 1, suggesting low sun exposure risk. As the day progresses, a noticeable shift occurs; by 9:00, the index climbs to 3, marking the onset of stronger rays. The peak is reached at 1:00 PM and 2:00 PM, where the UV Index soars to an intense 10, indicating very high exposure risk, making sun protection vital. Post-peak, from 3:00 PM onward, the index gradually declines, settling to 5 by 5:00 PM and dwindling further to low levels of 1 by 7:00 PM. This data underscores the importance of being sun-smart during those midday hours when UV radiation is strongest.
| 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 | 4 | 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 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
The UV Index varies significantly throughout the year, with notable increases during the warmer months. High-risk months include April through September, when the UV Index reaches its peak, particularly in June at an extreme level of 11. During these months, the burn time shortens dramatically, with a maximum exposure of just 10 minutes in June to avoid skin damage. Conversely, the winter months of January, February, November, and December exhibit a moderate risk, allowing for longer exposure times of 30 minutes. Visitors and residents are advised to take precautions during the high-risk period, including wearing sunscreen, protective clothing, and limiting sun exposure, especially between the hours of 10 AM and 4 PM when UV radiation is the strongest.
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 |
| Sao Martinho do Porto | 3 | 5 | 6 | 9 | 9 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| 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 |