Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors in Coimbra, Portugal, where the Mediterranean climate brings powerful sun exposure, especially during the summer months. With UV levels reaching a maximum of 11 at midday, awareness of these levels is vital for sunburn prevention and maintaining overall skin health. As the sun shines brightly, knowing when to seek shade and how to protect your skin can make all the difference in enjoying the warm, sunny days that Coimbra has to offer while keeping harmful UV rays at bay.
As the sun climbs higher, the UV Index takes a dramatic leap throughout the day. Starting at a gentle 1 at 07:00, it gradually rises to 3 by 09:00. The real intensity kicks in later, peaking at an impressive 11 around 13:00, a critical time when sun protection is essential. From there, a gradual decline begins, with readings of 10 at 14:00, 9 at 15:00, and tapering off to 3 by 18:00. Finally, the day winds down, returning to 1 by 19:00. It’s a vivid reminder of how important it is to safeguard against UV exposure during the sun’s most potent 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 | 11 | extreme | 10 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 |
Throughout the year, seasonal changes in UV Index reveal significant fluctuations in sun exposure and risk levels. The months of March through September present the highest UV levels, with April through June reaching the peak UV Index of 11 in June, categorized as extreme, while May and July also remain dangerously high. High-risk months for sunburn are clearly identified as April to September, where the burn time decreases sharply to as little as 10 minutes in June. As such, it is crucial for both visitors and residents to take precautionary measures during these months. This includes wearing sunscreen, donning protective clothing, and seeking shade during peak hours, particularly from late morning to mid-afternoon, to mitigate skin damage and health risks associated with UV exposure.
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 |
| Coimbra | 3 | 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 |