Last updated: June 2, 2025
Understanding the UV Index is essential for residents and visitors of Williston, South Africa, as it informs us about the intensity of harmful ultraviolet radiation from the sun. Being aware of UV levels is crucial not just for preventing painful sunburns, but also for maintaining long-term skin health and reducing the risk of skin cancer. In Williston, classified under the BWk climate zone, UV exposure can vary significantly, peaking around midday with levels reaching up to 4. This means that even short periods of sun exposure can lead to skin damage. Stay informed and protect your skin by checking the UV Index before stepping out!
The UV Index throughout the day clearly illustrates its early morning calm before reaching the peak around midday. Starting at a maximum of 0 at 07:00, the index gradually rises to 1 by 08:00 and remains slight until it hits 2 at 10:00. The real intensity is felt between 11:00 and 13:00, where it peaks at 4, emphasizing the importance of sun protection during these hours. As the afternoon unfolds, the index steadily declines, dropping back to 2 by 15:00 before tapering off to 1 at 16:00 and returning to 0 by 18:00. Overall, this data underscores the significant variation of UV exposure throughout the day, encouraging us to be mindful of sun safety during its highest points.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 0 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 1 | low | 45 min |
| 10:00 | 2 | low | 45 min |
| 11:00 | 4 | moderate | 30 min |
| 12:00 | 4 | moderate | 30 min |
| 13:00 | 4 | moderate | 30 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 the highest levels occurring from January to March, and again in September, October, and November. These months present high-risk conditions, as indicated by an extreme UV Index of 15 and 16, necessitating a burn time of only 10 minutes for unprotected skin. April sees a notable decrease to a very high level, with a UV Index of 9 and a burn time of 15 minutes. Visitors and residents are advised to exercise extreme caution during these high-risk months by wearing protective clothing, using broad-spectrum sunscreen, and seeking shade when outdoors. As summer approaches, the UV Index moderates in June and July but still warrants attention, particularly in August. To minimize skin damage, it is essential to stay vigilant and take necessary precautions throughout the year.
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 |
| Williston | 15 | 15 | 12 | 9 | 6 | 4 | 5 | 7 | 11 | 12 | 14 | 16 |
| 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 |
| Soweto UVI | 16 | 15 | 13 | 11 | 7 | 6 | 6 | 8 | 11 | 13 | 15 | 16 |