Last updated: July 2, 2025
Understanding the UV Index is crucial for residents of Louisville, United States, as it serves as a daily guide to the sun’s intensity and potential risk of skin damage. With peaks reaching an alarming 11 during midday hours, awareness of UV levels is essential for preventing sunburn and maintaining long-term skin health. Louisville's Cfa climate means residents enjoy ample sunshine, but it also brings elevated UV exposure risks, especially in the summer. By monitoring the UV Index, you can make informed decisions about sun protection, ensuring you enjoy the outdoors while safeguarding your skin.
The UV Index throughout the day reveals a fascinating journey of sun exposure. Starting at a gentle level of 1 at 07:00 and 08:00, the index begins to rise steadily, hitting 3 by 09:00. As the sun reaches its peak, the intensity escalates dramatically, soaring to 10 at noon and peaking at 11 from 13:00 to 14:00—ideal for sun protection measures! The afternoon sees a gradual decline, with values dropping to 9 at 15:00, then further diminishing to 2 by 18:00, and finally settling back at 1 by 19:00. Whether lounging in the sun or engaging in outdoor activities, awareness of this UV landscape is essential for safe enjoyment!
| 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 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 7 | high | 25 min |
| 17:00 | 5 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, UV Index levels exhibit noteworthy seasonal changes, with high-risk months identified from March to August, when exposure reaches very high or extreme levels. In March and April, the UV Index peaks at 9 and 10, respectively, indicating a transition into the more hazardous summer months. May through August experience the highest UV Index of 11, categorized as extreme, which necessitates diligent sun protection within a burn time of just 10 minutes. As September and October arrive, UV levels remain considerable, with a very high index of 9 and 8, and slowly tapering off towards the end of the year. It is crucial for both visitors and residents to take appropriate precautions during these months, such as wearing sunscreen, protective clothing, and seeking shade during peak hours to minimize the risk of UV-related skin damage.
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 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Louisville | 4 | 7 | 9 | 10 | 11 | 11 | 11 | 11 | 9 | 8 | 6 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |