Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Modderfontein, South Africa, as it provides essential information about the intensity of ultraviolet radiation from the sun. By being aware of UV levels, you can effectively prevent sunburn and safeguard your skin health against the long-term effects of excessive sun exposure. With a Cwa climate characterized by warm summers and mild winters, Modderfontein sees varying UV exposure risks throughout the day—peaking at a UV Index of 6 around noon. Stay informed and protect yourself from harmful rays by keeping a close eye on the daily UV Index!
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 |
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 |