Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors of Randfontein, South Africa, as it serves as a vital tool for sunburn prevention and promoting long-term skin health. The UV levels in this Cwb climate zone can vary significantly throughout the day, with peak exposure occurring between 11:00 AM and 1:00 PM, when the UV Index hits a maximum of 7—indicating a high risk of harm from unprotected sun exposure. By staying informed about these levels, you can take proactive steps to protect yourself from potential skin damage while enjoying the beautiful sunny days that Randfontein has to offer.
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 radiation exposure exhibits significant seasonal variations, with the highest risk months peaking in January, February, and March, where the UV Index reaches an extreme level of 16 to 13, allowing for a dangerously short burn time of just 10 minutes. The trend continues into April and September, which also maintain an extreme UV Index of 11. As summer approaches, a slight decrease in UV Index is observed in May to July, with values ranging from 6 to 7, indicating a high exposure risk but allowing for longer burn times of 25 minutes. However, high caution is advised during August when the UV Index spikes back to 8 (very high). As the year closes, November and December mirror the extreme levels seen at the start of the year, necessitating constant vigilance. Therefore, visitors and residents should adopt protective measures, such as wearing sunscreen and protective clothing, especially during peak UV times, and seek shade whenever possible, particularly in the high-risk months of January through March and September through November.
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 |
| Pretoria UVI | 16 | 15 | 13 | 10 | 7 | 6 | 6 | 9 | 11 | 13 | 14 | 16 |
| Randfontein | 16 | 15 | 13 | 11 | 7 | 6 | 6 | 8 | 11 | 13 | 15 | 16 |
| Soweto UVI | 16 | 15 | 13 | 11 | 7 | 6 | 6 | 8 | 11 | 13 | 15 | 16 |