Last updated: June 2, 2025
In Castro, Brazil, understanding the UV Index is crucial for protecting your skin and overall health. The UV Index indicates the strength of ultraviolet (UV) radiation from the sun, allowing residents to take timely precautions against sunburn and long-term skin damage. With a Cfb climate that features cool, humid conditions, Castro still poses significant UV exposure risks, especially during midday hours when the index reaches a peak of 6. Being informed about daily UV levels helps you enjoy the outdoors safely, ensuring you’re always prepared to shield yourself from harmful rays.
Throughout the day, the UV Index escalates to its peak between 12:00 PM and 1:00 PM, reaching a high of 6—a clear indicator to stay protected from the sun's rays. Early morning hours see a gentle start, with a maximum 1 at 7:00 AM and 8:00 AM, gradually rising to 2 by 9:00 AM. As the sun climbs, so does the intensity, spiking to 5 at 11:00 AM and maintaining a steady 6 for the peak hours. Following this brief burst of intensity, the UV Index dwindles swiftly, dropping to 4 by 2:00 PM, then further decreasing to 3 at 3:00 PM, and tapering off to 1 by 4:00 PM. Finally, as daylight fades, the index plummets to 0 by 6:00 PM, marking the end of a vibrant, sunlit day. Remember to stay safe and protect your skin, especially during midday hours!
| 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 | 5 | moderate | 30 min |
| 12:00 | 6 | high | 25 min |
| 13:00 | 6 | high | 25 min |
| 14:00 | 4 | 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 |
Throughout the year, UV exposure varies significantly, with the highest levels occurring from January to April and returning again in September to November. During these months, the UV Index peaks at 16, indicating an extreme risk of harm from unprotected sun exposure, with a burn time of just 10 minutes. May and August experience a slight reduction in risk, categorized as very high with an index of 8 and 9, respectively, thus extending the burn time to 15 minutes. The summer months of June and July show a decreased index of 6 and 7 with high exposure categories, allowing for longer exposure times of 25 minutes. Visitors and residents should exercise heightened caution during the high-risk months, ensuring adequate sun protection, such as sunscreen, clothing, and hats, especially during peak UV hours.
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 |
| Castro | 16 | 16 | 13 | 11 | 8 | 6 | 7 | 9 | 11 | 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 |