Last updated: August 1, 2025
Understanding the UV Index is crucial for residents and visitors in Sao Marcos, Brazil, where the subtropical climate can lead to varied sun exposure throughout the day. By keeping an eye on UV levels, you can take proactive steps to prevent sunburn and protect your skin health. Typically, during the midday hours, UV Index levels can reach up to 5, indicating a moderate risk of harm from unprotected sun exposure. With Sao Marcos experiencing a temperate climate, it's key to recognize those peak times and safeguard against the potential risks of excessive UV radiation. Stay informed and enjoy the sun safely!
The UV index makes a gradual ascent throughout the morning, starting at a low of 0 at 07:00 and peaking at a moderate 5 from 12:00 to 13:00. As the sun reaches its zenith, UV exposure is at its highest, making it essential to protect your skin during these hours. After 13:00, the index begins its descent, dropping back to a relatively low value of 3 by 15:00 and further down to 1 towards the evening. As the sun sets at 18:00, the UV index returns to 0, signaling a safe end to sun exposure for the day. Enjoy the sun, but remember to stay sun-smart during those 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 | 8 | very high | 15 min |
| 13:00 | 7 | high | 25 min |
| 14:00 | 6 | high | 25 min |
| 15:00 | 4 | moderate | 30 min |
| 16:00 | 2 | 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 |