Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Modderfontein, South Africa, where sun exposure can vary significantly throughout the day. With an average climate categorized as Cwa, this area experiences distinct seasonal changes that can affect UV levels, making awareness vital for prevention of sunburn and promotion of skin health. During peak hours—particularly between 11:00 AM and 1:00 PM—the UV Index often reaches levels of 7, indicating a high risk of harm from unprotected sun exposure. Being informed about these fluctuations empowers you to take proactive measures in safeguarding your skin and enjoying the beautiful South African sun responsibly.
As the sun rises, the UV Index remains low at 1 from 07:00 to 08:00, offering a gentle start to the day. However, as the hours progress, the intensity increases, reaching 3 by 09:00 and peaking at 7 between 11:00 and 13:00. This midday surge signifies the sun's powerful rays, urging everyone to take precautions for skin protection. As the afternoon wanes, the UV Index begins to decline, dropping to 5 at 14:00, and further decreasing to 3 by 15:00. The evening brings relief, with the index falling to 1 by 16:00 and 0 from 18:00 onward. Embrace the early hours for outdoor activities, but stay vigilant during lunchtime when the sun is at its strongest!
| 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 | 7 | high | 25 min |
| 13:00 | 7 | 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 |
Throughout the year, UV exposure varies significantly, with extreme UV Index levels observed from January to March and again in September to November. Notably, January and December each reach a peak UV Index of 16, indicating a very high risk of harm from unprotected sun exposure, with a burn time of just 10 minutes. The transition months of April and August present very high exposure conditions, while May to July see a shift to high categories, allowing slightly longer burn times of 25 minutes. As the sun’s intensity increases, it is crucial for both visitors and residents to take protective measures, especially during the high-risk months of January, February, March, September, October, and November. Umbrellas, sunscreen, protective clothing, and seeking shade during peak hours are highly recommended to ensure safety against the harmful effects of UV radiation.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cape Town UVI | 14 | 13 | 11 | 8 | 5 | 3 | 4 | 6 | 9 | 11 | 12 | 14 |
| Durban UVI | 14 | 13 | 12 | 9 | 6 | 4 | 5 | 7 | 9 | 11 | 13 | 15 |
| Johannesburg UVI | 15 | 15 | 13 | 10 | 7 | 6 | 6 | 8 | 11 | 12 | 14 | 16 |
| Modderfontein | 16 | 15 | 13 | 10 | 7 | 6 | 6 | 9 | 11 | 13 | 14 | 16 |
| Pretoria UVI | 16 | 15 | 13 | 10 | 7 | 6 | 6 | 9 | 11 | 13 | 14 | 16 |
| Soweto UVI | 16 | 15 | 13 | 11 | 7 | 6 | 6 | 8 | 11 | 13 | 15 | 16 |