Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Knoxville, United States, where sunny days can quickly lead to harmful exposure. The UV Index provides essential information about the sun's ultraviolet radiation levels, helping you take proactive steps to prevent sunburn and protect your skin health. With Knoxville's humid subtropical climate, the risk of high UV exposure peaks during midday hours, reaching levels as high as 11 around noon. By being aware of these levels, you can enjoy the great outdoors safely while keeping your skin protected from the sun's potential damage. Keep an eye on the UV Index to enjoy sunny days in Knoxville without compromising your health!
The UV Index for the day reveals a dynamic shift in sun exposure, starting off low in the early morning hours with values of 1 at both 7:00 and 8:00. As the sun climbs higher, the index ramps up, peaking at an intense 11 between 13:00 and 14:00—a clear signal for sun safety measures. This period of maximum intensity comes after a sharp rise from 3 at 9:00 to a notable 7 at 11:00. The afternoon provides a gradual decline, with levels falling to 9 by 15:00, then tapering off to 3 by 18:00 before returning to a safe 1 at 19:00. It's a solid reminder to stay protected during peak hours!
| 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 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
The UV Index exhibits significant seasonal variation, peaking during the summer months. From January (UV Index 4) to February (UV Index 7), exposure remains moderate to high, with burn times shortening as spring approaches. The months of March and April see a sharp increase in UV levels (9 and 10 respectively), indicating very high risk for sunburn, with a burn time of just 15 minutes. The extreme category dominates from May to August (UV Index 11), where even brief sun exposure can result in burns within 10 minutes. As we move into September and October, the index drops to 10 and 8, maintaining a very high risk, before returning to a moderate level in November and December (UV Index 6 and 4). Visitors and residents are strongly advised to take precautions, especially from March through October, by wearing protective clothing, using sunscreen, and seeking shade during peak sun hours to minimize the risk of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Knoxville | 4 | 7 | 9 | 10 | 11 | 11 | 11 | 11 | 10 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |