Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Alfenas, Brazil, especially given its unique Cwa climate with varying sun exposure throughout the day. Knowledge of UV levels plays a key role in preventing sunburn and promoting long-term skin health. With peak UV readings reaching an intensity of 8 at noon, it’s essential to take precautions to protect yourself during the hottest hours. Alfenas, often blessed with sunny days, can pose significant UV exposure risks, making awareness not just beneficial, but vital for your well-being. Stay informed and shield your skin—your future self will thank you!
The UV Index throughout the day presents a clear pattern, peaking around noon with a maximum value of 8, indicating that sun protection is crucial during this time. Starting from a low of 1 at 07:00 and 08:00, the index rises steadily, hitting 5 by 10:00. It escalates to its highest point at 12:00, before gradually declining to 7 at 13:00 and then dropping further as the afternoon progresses. By 16:00, the index has decreased to 2, and finally, it settles to 0 by 18:00, meaning minimal risk of harm from sun exposure as daylight fades. For outdoor enthusiasts, the best advice is to stay safe and protect against UV rays, especially around midday!
| 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 | 5 | moderate | 30 min |
| 15:00 | 3 | 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 |
The UV Index shows significant seasonal variation, with the highest readings occurring from January to April, where the index reaches an extreme 16. These months pose a high risk for sunburn, with a critical 10-minute burn time. After April, the index slightly decreases, but remains very high in May (8) and July (8), and high in June (7). As summer transitions into fall, the UV Index fluctuates but remains concerning, especially in September (12) and October (14), both categorized as extreme, again allowing only a short 10-minute exposure without protection. The end of the year is marked by high indices once more, peaking in December at 16. Visitors and residents are strongly advised to take protective measures against UV exposure, particularly during these high-risk months 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 |
| Sao Paulo UVI | 16 | 15 | 12 | 11 | 8 | 6 | 7 | 9 | 11 | 13 | 14 | 15 |
| Alfenas | 16 | 16 | 13 | 11 | 8 | 7 | 8 | 10 | 12 | 14 | 15 | 16 |
| 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 |