Last updated: July 2, 2025
In Tres Rios, Brazil, understanding the UV Index is essential for maintaining skin health and preventing painful sunburns. With its Cfa climate, this picturesque region experiences substantial sun exposure, particularly during midday hours when the UV levels can reach up to 8. Being aware of these fluctuations—from a low of 1 early in the morning to the peak at noon—empowers residents and visitors alike to take proactive steps towards protection, ensuring their outdoor enjoyment is both safe and enjoyable. Stay informed and safeguard your skin against harmful UV rays while basking in the beauty of Tres Rios!
As the sun rises, the UV Index begins its ascent, starting at a mild 1 at 07:00. By 08:00, it gently climbs to 2, but it's not until 09:00 that it hits 3, signaling a clearer sky. The index takes a notable leap at 10:00, reaching a brisk 5, and peaks at 12:00 with a striking 8—the ideal time to seek shade or apply sunscreen! As the afternoon wears on, the index falls back to 7 at 13:00, and then gradually drops to 5 by 14:00. As the sun starts to set, there's a further decline, leaving the evening with a relaxed 1 at 16:00 and tapering off to 0 by 19:00. This detailed hour-by-hour progression highlights the importance of sun safety during the peak hours of the day!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | 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 | 5 | moderate | 30 min |
| 15:00 | 3 | moderate | 30 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 |
The UV Index experiences significant seasonal changes, with the highest levels occurring during the first half of the year. The high-risk months are from January to April and September to November, where the UV Index consistently falls within the extreme category, peaking at 16 in January and steadily remaining high through October with levels around 13-15. During these months, burn time is as short as 10 minutes, emphasizing the need for heightened sun protection measures. Conversely, the UV Index drops slightly in June and July, reaching a very high level of 6-8, with a more manageable burn time of 15-25 minutes. Visitors and residents are advised to remain vigilant year-round, particularly during high-risk periods, by using sunscreen, wearing protective clothing, and seeking shade whenever possible to minimize sun damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 |
| Tres Rios | 16 | 15 | 13 | 11 | 8 | 6 | 8 | 10 | 12 | 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 |