UV Index in Knoxville, United States

Last updated: May 3, 2025

In Knoxville, United States, being aware of the UV Index is essential for protecting your skin from harmful ultraviolet rays. Understanding the daily UV levels can significantly reduce the risk of sunburn and long-term skin health issues. With its humid continental climate, Knoxville experiences a varied and sometimes intense sun exposure, especially during peak hours when UV levels can soar to a dangerous 9. Staying informed about the UV Index not only helps you enjoy the beautiful outdoors safely but also promotes healthier habits year-round.

Hourly UV Index in Knoxville

The UV Index throughout the day presents a clear pattern of intensity, peaking at midday. Starting from a mild level of 1 at 07:00, the index rises steadily, reaching 2 by 08:00. The real surge occurs between 09:00 and 13:00, where it escalates from 4 to a striking 9—the highest point of the day. As the afternoon unfolds, the intensity slightly declines to 7 at 15:00, before tapering off to 5 at 16:00. The evening sees a further decrease, settling back to 2 by 18:00 and returning to 1 at 19:00. For those enjoying outdoor activities, it’s essential to take precautions, especially during the peak hours from 11:00 to 14:00 when the UV rays are most potent.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	2	low	45 min
09:00	4	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	9	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Knoxville

Throughout the year, UV exposure varies significantly, with the highest risk months occurring from April to September when the index reaches very high to extreme levels. Specifically, June stands out with a UV Index of 11, where a mere 10 minutes of unprotected sun exposure can lead to skin damage. In contrast, during the winter months of January and February, the UV Index remains lower, categorized as moderate, allowing for a safer 30-minute burn time. Visitors and residents are advised to take necessary precautions during high-risk months, such as applying broad-spectrum sunscreen, wearing protective clothing, and seeking shade during peak sunlight hours, to minimize their risk of UV-related skin damage.

Monthly Maximum UV Index for Knoxville, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Knoxville. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Knoxville, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Knoxville UV Index with Other United States Cities

The table above highlights how UV exposure in Knoxville compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Knoxville's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	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
Knoxville	3	5	6	8	9	11	10	9	8	6	4	2
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5