Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Biritiba Mirim, Brazil, as it empowers individuals to protect their skin from harmful ultraviolet radiation. With the region's Cfa climate, the sun can be particularly intense, especially during midday hours, making awareness of UV levels essential for sunburn prevention and overall skin health. As UV exposure peaks at levels 6 to 4 between 11:00 AM and 2:00 PM, it's vital for locals to stay informed and take necessary precautions during these high-risk periods. By monitoring the UV Index, you can enjoy the beautiful sun-soaked days of Biritiba Mirim while safeguarding your skin's well-being.
The UV Index throughout the day presents an interesting fluctuation, starting off quite low with a maximum of 1 at both 07:00 and 08:00. As the sun rises higher, the intensity increases sharply, peaking at 6 from 11:00 to 13:00. This is the critical time to protect your skin, as a UV Index of 6 indicates a moderate risk of harm from unprotected sun exposure. The afternoon sees a gradual decline, with numbers dropping back to 2 by 15:00 and returning to 1 by 16:00 and 17:00. Finally, as the day comes to a close, the UV Index falls to 0 by 18:00 and remains there through the evening, reminding us that while the sun's rays can be strong during the day, they also retreat as the sun sets.
| 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 | 6 | high | 25 min |
| 12:00 | 6 | high | 25 min |
| 13:00 | 6 | high | 25 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 |
The UV Index exhibits significant seasonal changes, peaking between January and April with extreme levels ranging from 15 to 16, which translates to a rapid burn time of just 10 minutes. Following this intense period, May marks a decrease to a very high index of 8, with a slightly longer burn time of 15 minutes. From June to July, the UV exposure remains high, with indices of 6 to 7, allowing for up to 25 minutes of safe sun exposure. As summer fades, August sees a rise again to a very high index of 9, followed by a return to extreme levels in September and throughout the fall months into December, where the index consistently hovers around 14 to 15 with a 10-minute burn time. Consequently, the highest risk months for UV exposure are from January to April and September to November. Visitors and residents are strongly advised to take necessary precautions during these periods, such as using sunscreen, wearing protective clothing, and seeking shade to minimize the risk of sunburn and long-term skin 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 |
| Biritiba Mirim | 16 | 15 | 12 | 11 | 8 | 6 | 7 | 9 | 11 | 13 | 14 | 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 |