UV Index in Louisville, United States

Last updated: June 2, 2025

In Louisville, United States, staying informed about the UV Index is crucial for protecting your skin and overall health. Understanding UV levels helps you prevent sunburn, reduce the risk of skin cancer, and promote long-term skin health. With Louisville's BSk climate, which brings warm summers and a fair amount of sunshine, residents should be particularly cautious during peak UV times, especially between 10 AM and 2 PM when the index can soar to 12. By keeping an eye on the UV Index, you can enjoy outdoor activities while minimizing harmful exposure.

Hourly UV Index in Louisville

At sunrise, the UV Index begins its steady climb, starting at a safe 1 at 07:00. As the morning progresses, it escalates to 2 by 08:00 and reaches a pleasant 4 by 09:00. However, the real intensity hits between 10:00 and 13:00, with the UV Index peaking at a scorching 12 at 12:00, indicating a high risk of harm from unprotected sun exposure. As the afternoon unfolds, levels gradually descend, hitting 9 at 15:00 before tapering off to 4 by 17:00. By the evening hours, the index returns to a mild 1 by 19:00, reminding us of the importance of sunscreen amidst the sun's powerful midday rays.

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	7	high	25 min
11:00	10	very high	15 min
12:00	12	extreme	10 min
13:00	12	extreme	10 min
14:00	11	extreme	10 min
15:00	9	very high	15 min
16:00	6	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

During the year, UV levels vary significantly, with the most dangerous months being March to August, where the UV Index peaks at 12 in June and July, indicating an extreme risk of harm from unprotected sun exposure. April and May also maintain a very high to extreme rating, resulting in a rapid burn time of just 10 minutes. Conversely, during the winter months, such as January and December, the UV Index is at a more manageable 4, categorized as moderate, allowing for longer exposure times of 30 minutes without immediate risk. Residents and visitors are advised to exercise caution during the high-risk months by wearing sunscreen, protective clothing, and seeking shade, especially during peak hours when the sun's rays are most intense.

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
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Louisville	4	6	9	11	11	12	12	11	10	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5