Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Porto, Portugal, where sun exposure can vary significantly throughout the day. With the city's mild Mediterranean climate and peak UV levels reaching 9 during the midday hours, being aware of these levels is essential for sunburn prevention and maintaining skin health. By monitoring the UV Index, you can make informed choices about when to seek shade, apply sunscreen, and protect yourself from the harmful effects of excessive sun exposure. Whether enjoying a stroll along the Douro River or exploring historic landmarks, keeping an eye on the UV Index will help ensure your sun-soaked adventures in Porto remain safe and enjoyable.
The UV Index throughout the day shows a notable peak around midday, reaching a maximum of 9 at both 12:00 PM and 1:00 PM. Early in the morning, from 7:00 AM to 8:00 AM, the index remains at a low 1, indicating minimal UV exposure. As the day progresses, it gradually rises, hitting 5 by 10:00 AM and surging to 7 by 11:00 AM. The intensity continues to climb until it stabilizes at 9 during the hottest hours before gradually descending after 3:00 PM, dropping to 4 by 5:00 PM and returning to a comfortable 1 by 7:00 PM. For those planning outdoor activities, it's crucial to take precautions during the peak hours of 12:00 PM to 2:00 PM to avoid harmful UV exposure.
| 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 | 9 | 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 |
As the seasons change, so do the UV levels, which significantly impact skin safety for both visitors and residents. The UV Index starts low in January (2) and December (2), indicating a low risk for sunburn. However, as we move into the spring and summer months, particularly from March (6) to August (9), the risk escalates, with April (8) and the peak in June (11) classified as extreme. The high-risk months are primarily from April through August, where burn times are notably short, especially in June, with only 10 minutes until skin damage occurs. It is crucial for individuals during these months to take necessary precautions, such as wearing sunscreen, protective clothing, and limiting sun exposure, especially during peak hours. As fall approaches, the UV Index gradually decreases, but awareness remains essential for safe outdoor activities.
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 | 2 | 4 | 6 | 8 | 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 |