UV Index in Louisville, United States

Last updated: May 3, 2025

Understanding the UV Index is crucial for residents of Louisville, United States, as it directly impacts your skin health and the risk of sunburn. With the city’s Dfa climate bringing warm summers and sunny days, knowing the UV levels can help you safeguard yourself against harmful exposure. Typically peaking at a UV Index of 10 around midday, it’s essential to stay informed about daily fluctuations and protect your skin accordingly. Being aware of these levels not only promotes better sun safety practices but also enhances your overall well-being when enjoying the beautiful outdoors in Louisville.

Hourly UV Index in Louisville

The UV Index throughout the day presents a clear narrative of rising intensity, peaking in the afternoon. Starting at 1 by 07:00, the UV levels gradually ascend, reaching 5 by 10:00. By 11:00, the index climbs to 7, and it soars to a striking 10 at 13:00—the optimal time for sun precautions. The intensity slightly wanes thereafter, dropping to 9 at 14:00 and continuing down to 4 by 17:00. As evening approaches, the UV Index dwindles to 1 by 19:00, signaling a return to safer levels. This data underscores the importance of sun safety measures during peak hours, particularly between 11:00 and 14:00.

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	1	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	9	very high	15 min
15:00	8	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

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