Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of Sao Francisco do Sul, Brazil, where the sun can be both a source of warmth and a potential risk to skin health. Awareness of UV levels is essential for effective sunburn prevention and to protect against long-term skin damage, especially during midday when the index peaks at 7. Nestled in a Cfa climate zone, Sao Francisco do Sul experiences a temperate climate, but its UV exposure can escalate quickly, underscoring the importance of checking the UV Index regularly. By understanding how UV levels fluctuate throughout the day, you can enjoy the outdoors safely while safeguarding your skin.
The UV Index data for the day reveals a dynamic pattern of sun exposure. Starting off at a low level, both 7:00 AM and 8:00 AM maintain a mere index of 1, indicating minimal UV radiation. As the sun climbs higher, 9:00 AM sees the index rise to 3, gradually peaking at 12:00 PM with an intense 7, suggesting it's time for sun protection. The afternoon hours show a slight decline, with 1:00 PM and 2:00 PM still holding strong at 6 and 5 respectively. As the day winds down, the index drops sharply after 3:00 PM, falling back to a 1 by 4:00 PM and eventually reaching 0 by 6:00 PM, marking a safe return from the sun's harsh rays. It's a reminder of the importance of sun safety during those midday hours!
| 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 | 4 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 7 | high | 25 min |
| 13:00 | 6 | 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 exhibits significant seasonal variations, peaking at extreme levels from January to March and again in October through December, with values soaring to 15. Notably, February and November also maintain an index of 14, indicating extremely high risks for sunburn, with minimal burn times of just 10 minutes. Transitioning into the spring and summer months, the UV Index decreases to a very high level of 10 in April and 8 in August, while the burn time gradually increases to 15 and 25 minutes in May and June, respectively. July and August maintain a high risk, with burn times extending to 25 minutes, before returning to very high in September. Given these data, it's crucial for visitors and residents alike to practice sun safety—especially from January through March and again from October to November—by seeking shade, wearing protective clothing, and applying sunscreen regularly to mitigate the risk of UV exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sao Francisco do Sul | 15 | 14 | 12 | 10 | 7 | 6 | 6 | 8 | 10 | 13 | 14 | 15 |
| 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 |
| 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 |