Last updated: July 2, 2025
In the vibrant city of Sao Luis, Portugal, understanding the UV Index is crucial for safeguarding your skin health against harmful ultraviolet radiation. With the region's Mediterranean climate often exposing residents to high UV levels, being aware of the daily index can help prevent painful sunburns and reduce long-term skin damage. From morning to afternoon, UV exposure rises significantly, peaking at a risky level of 10 around 1 PM and 2 PM. By staying informed about UV indices, you can enjoy the sun safely while keeping your skin healthy in this beautiful coastal town.
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 |
Seasonal changes in UV radiation show a significant increase from late winter through summer, peaking during the hotter months. High-risk months with extreme UV levels include June (UV Index 11) and July to August (UV Index 10), where the burn time is as little as 10 to 15 minutes. Visitors and residents should take precautionary measures during these months, such as wearing protective clothing, using broad-spectrum sunscreen, and minimizing sun exposure between 10 AM and 4 PM. As fall approaches, UV levels gradually decrease, but it remains important to stay aware, particularly in March through October, when the UV index often enters the high to very high categories.
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 |
| 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 |
| Sao Luis | 3 | 5 | 6 | 9 | 10 | 11 | 10 | 10 | 9 | 7 | 4 | 3 |