Last updated: May 3, 2025
In Louisville, United States, being aware of the UV Index is crucial for anyone who enjoys the sunny outdoors. Understanding UV levels is key to preventing sunburn and protecting your skin health, especially as UV exposure can lead to long-term damage. With a Cfa climate, Louisville experiences notable UV risks, particularly during the midday hours when the index can soar to highs of 10. Whether you're planning a family picnic or a leisurely stroll along the river, being conscious of the UV Index can help you stay safe while enjoying the beautiful Kentucky sun.
The UV index throughout the day reveals a stunning escalation in solar intensity, peaking at 10 between 1:00 PM and 2:00 PM. Morning hours start off comfortably with a UV index of 1 at 7:00 AM and gradually rising to 2 by 9:00 AM. As the sun climbs higher, however, watch for a significant uptick: it soars to 4 by 10:00 AM, and then leaps to 7 at 11:00 AM. The afternoon demands attention, with values reaching 9, then hitting their zenith at 10. Thankfully, as evening approaches, the UV levels gracefully decline to 4 at 5:00 PM, and further drop to 1 by 7:00 PM. Remember to protect your skin during those peak hours, especially between noon and 2 PM!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | 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 | 3 | moderate | 30 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, so does the UV Index, which indicates the strength of ultraviolet radiation and the associated risk of harm from sun exposure. High-risk months for UV exposure typically occur from March through September, peaking in June with an extreme Index of 11 and a burn time of just 10 minutes. April and May are also notably hazardous, with very high UV ratings of 9 and 10 respectively. During these months, it is crucial for visitors and residents to take protective measures, such as wearing sunscreen, protective clothing, and seeking shade during peak hours. Conversely, during the winter months of January, November, and December, the UV Index is moderate, allowing for longer exposure times of up to 30 minutes without immediate risk. Always stay informed and prioritize sun safety to enjoy the outdoors responsibly throughout the year.
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 |
| Louisville | 3 | 5 | 7 | 9 | 10 | 11 | 10 | 10 | 8 | 7 | 4 | 3 |
| 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 |