Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Knysna, South Africa, where the sun's rays can pose significant risks. The UV Index is a vital tool for gauging ultraviolet radiation levels throughout the day, helping to inform decisions that protect skin health and prevent painful sunburns. With a temperate maritime climate, Knysna enjoys plenty of sunshine but also presents unique UV exposure risks, particularly during the midday hours when the index peaks at 5. By staying informed about the UV Index, you can enjoy Knysna’s stunning natural beauty while taking the necessary precautions for safe sun exposure.
The UV Index for the day begins at a safe 0 at 07:00, making it the perfect time for morning activities. As the sun rises, the index gradually climbs to 1 by 08:00 and 2 by 09:00. The intensity peaks between 11:00 and 13:00, reaching a maximum value of 5—a key time for sun protection! Following this, the UV levels gradually decline, dropping to 4 at 14:00 and then tapering off to 3 by 15:00. As afternoon gives way to evening, the UV Index decreases steadily to 1 at 17:00 and finally back to 0 by 19:00. Remember to enjoy the sun responsibly during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 0 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 3 | moderate | 30 min |
| 11:00 | 5 | moderate | 30 min |
| 12:00 | 5 | moderate | 30 min |
| 13:00 | 5 | moderate | 30 min |
| 14:00 | 4 | 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 experiences significant seasonal fluctuations, peaking during the winter months. January and February record an extreme UV Index of 14 and 13 respectively, with a rapid burn time of just 10 minutes. This trend continues into March with an index of 11. As spring arrives in April, the UV Index drops to 8 (very high), allowing for 15 minutes of exposure before burning occurs. From May to July, the UV Index levels decrease to 5 and 4 (moderate), extending burn times to 30 minutes. However, the UV exposure rises again in late summer, with August at 6 (high) and 25 minutes of burn time. As fall approaches, the UV levels rebound in September to 9 (very high) before shifting back to extreme levels in October (11) and November (12), both with a burn time of 10 minutes. December mirrors January, reaching UV levels of 14. Visitors and residents should take precautionary measures during high-risk months (January to March, October to November) by applying sunscreen, wearing protective clothing, and limiting sun exposure during peak hours to mitigate the risks associated with high UV exposure.
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 |
| Knysna | 14 | 13 | 11 | 8 | 5 | 4 | 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 |
| Soweto UVI | 16 | 15 | 13 | 11 | 7 | 6 | 6 | 8 | 11 | 13 | 15 | 16 |