UV Index in Louisville, United States

Last updated: June 2, 2025

In Louisville, Kentucky, being aware of the UV Index is crucial for maintaining skin health and preventing sunburn. Understanding the daily UV levels can help you make informed decisions about sun protection, especially during the peak hours when the index reaches a high of 10 around noon. With a Dfa climate, Louisville experiences significant UV exposure, particularly in the summer months, making it essential to stay protected against harmful ultraviolet rays. Whether you’re enjoying a day at the park or working outdoors, knowing how the UV Index fluctuates can safeguard your skin and overall well-being.

Hourly UV Index in Louisville

The UV Index data for the day reveals a notable rise in solar intensity, peaking at 10 between 1:00 PM and 2:00 PM. Starting from a gentle 1 at 7:00 AM, the index steadily climbs as the sun ascends, reaching a moderate 5 by 10:00 AM, and then surging to 9 at 12:00 PM. As the clock strikes 1:00 PM, the maximum UV Index of 10 alerts outdoor enthusiasts to take precautions. After this peak, a gradual decline begins, dropping to 4 by 5:00 PM, and the day winds down with readings back to 1 by 7:00 PM. Monitoring these fluctuations is essential for enjoying the sunshine safely!

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	3	moderate	30 min
10:00	5	moderate	30 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	10	very high	15 min
14:00	10	very high	15 min
15:00	9	very high	15 min
16:00	7	high	25 min
17:00	4	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Louisville

Throughout the year, UV exposure varies significantly, peaking in the late spring and summer months. April to August represent the high-risk period, with UV Index values reaching 10; indicating a very high exposure category and a burn time as short as 15 minutes. Visitors and residents should exercise caution and take protective measures, such as wearing sunscreen and protective clothing during these months. In contrast, January and December have moderate and low UV levels, respectively, with longer burn times of 30 to 45 minutes. Action is still advisable during these months, but the intensity is notably lower, allowing for safer outdoor activities. Overall, awareness of seasonal UV changes is essential for protecting skin health year-round.

Monthly Maximum UV Index for Louisville, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Louisville. 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 Louisville, 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 Louisville UV Index with Other United States Cities

The table above highlights how UV exposure in Louisville 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.

Louisville'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
Louisville	3	5	6	8	10	10	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