Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors in Brazil and the United States, where sun exposure can significantly impact skin health. By tracking UV levels, you can effectively prevent sunburn and minimize the long-term risks of skin damage. Brazil's warm Cfa climate often leads to higher UV exposure, especially during mid-day when the index peaks at 11. Armed with this knowledge, you can enjoy the sun safely while protecting yourself from its potentially harmful effects!
At dawn, the UV Index starts gently, peaking at 1 by 07:00 and 08:00, making it a safe time for early morning strolls. As the day progresses, the intensity gradually increases, reaching 4 by 10:00 and soaring to a striking 9 by noon. The sun reaches its zenith around 13:00, with a blistering 10, and even escalates to an impressive 11 by 14:00—the highest point of the day. As afternoon turns to evening, the index retreats; it dips to 8 by 16:00 and further down to a moderate 3 by 18:00, offering a more comfortable environment for outdoor activities. By 19:00, the UV intensity settles at a humble 2, signalling that the sun is winding down, making way for a lovely evening.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 9 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 10 | very high | 15 min |
| 16:00 | 8 | very high | 15 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
Throughout the year, seasonal changes in UV Index levels highlight varying risks associated with sun exposure. From January to February, UV levels remain moderate, with burn times of 30 minutes, making it a relatively safer period for outdoor activities. However, as March approaches, the UV Index escalates to 6, indicating higher caution is needed. The spring and summer months show a significant increase, peaking in June with an extreme UV Index of 11, where burn time reduces to just 10 minutes. High-risk months include April through August, with very high to extreme levels; visitors and residents should take extra precautions, like wearing sunscreen, hats, and protective clothing during these months. As the year progresses into October and November, UV levels decrease, returning to moderate levels by December, providing a safer environment for outdoor enjoyment. It’s essential for everyone to stay informed about UV levels and adjust their sun safety practices accordingly.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Brazil | 3 | 5 | 6 | 9 | 10 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |