Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Santo Tirso, Portugal, as it serves as a vital indicator of solar radiation exposure throughout the day. With the local climate categorized as Csb, which features a temperate environment, it's essential to monitor UV levels to effectively prevent sunburn and promote skin health. The UV Index in Santo Tirso reaches its peak between 11:00 AM and 2:00 PM, where levels can soar to 11, significantly increasing the risk of harmful effects on the skin. By staying informed about UV exposure, you can enjoy the beautiful Portuguese sunshine while safeguarding your health.
The UV Index for the day reveals a dynamic shift in sun exposure, starting off low in the early morning hours with values of 1 at both 7:00 and 8:00. As the sun climbs higher, the index ramps up, peaking at an intense 11 between 13:00 and 14:00—a clear signal for sun safety measures. This period of maximum intensity comes after a sharp rise from 3 at 9:00 to a notable 7 at 11:00. The afternoon provides a gradual decline, with levels falling to 9 by 15:00, then tapering off to 3 by 18:00 before returning to a safe 1 at 19:00. It's a solid reminder to stay protected during 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 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 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 |
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 |
| Santo Tirso | 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 |