Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Sao Marcos, Brazil, where the unique Cfb climate presents specific challenges and risks associated with ultraviolet radiation. With UV levels peaking at 5 during midday hours, awareness of these figures can significantly impact sunburn prevention and overall skin health. The interplay of sunlight and local climate means that even moderate UV exposure can lead to long-term skin damage. By staying informed about UV Index values, you can better protect yourself and enjoy the beautiful, sunny days in Sao Marcos while minimizing your risk of skin-related issues.
At dawn, the UV Index begins at a gentle 0 by 07:00, indicating minimal exposure risk. As the sun rises higher, the index steadily climbs, reaching 1 at 08:00 and peaking at 5 between 12:00 and 13:00, when the sun’s rays are at their most intense. During these peak hours, it’s wise to don your sunscreen and protective gear. Following this zenith, the index gracefully descends, dropping to 4 at 14:00 and tapering off to 2 by 15:00. As the afternoon fades to evening, the UV levels reduce significantly, returning to a safe 0 by 18:00. This hourly UV pattern underscores the importance of sun safety during peak daylight hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 0 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 3 | moderate | 30 min |
| 11:00 | 4 | moderate | 30 min |
| 12:00 | 5 | moderate | 30 min |
| 13:00 | 5 | moderate | 30 min |
| 14:00 | 4 | moderate | 30 min |
| 15:00 | 2 | low | 45 min |
| 16:00 | 1 | low | 45 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 0 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, the UV Index exhibits significant seasonal fluctuations, with extreme levels particularly pronounced from January to March and again in October to December. During these high-risk months, especially in January and February with an index of 15 and a burn time of just 10 minutes, individuals are at increased risk of skin damage. The spring months, notably April, shift to a very high exposure category with a UV Index of 10, while May and August mark a transition to high levels. From June to July, the UV Index lowers to moderate, allowing for slightly longer safe exposure times up to 30 minutes. As the season shifts back to autumn, September returns to very high, underlining the need for vigilance. To protect yourself, it's advisable for visitors and residents to utilize broad-spectrum sunscreen, seek shade, and wear protective clothing, especially during the extreme months of the year.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sao Marcos | 15 | 14 | 13 | 10 | 6 | 5 | 5 | 7 | 10 | 13 | 14 | 15 |
| Rio de Janeiro UVI | 15 | 14 | 13 | 10 | 7 | 6 | 7 | 9 | 11 | 12 | 13 | 15 |
| Sao Paulo UVI | 16 | 15 | 12 | 11 | 8 | 6 | 7 | 9 | 11 | 13 | 14 | 15 |
| Belo Horizonte UVI | 17 | 16 | 14 | 12 | 9 | 7 | 8 | 10 | 12 | 13 | 14 | 16 |
| Salvador UVI | 14 | 14 | 14 | 13 | 10 | 9 | 9 | 12 | 12 | 15 | 15 | 14 |
| Fortaleza UVI | 14 | 14 | 15 | 15 | 13 | 11 | 11 | 12 | 13 | 13 | 13 | 13 |