September weather forecast
Mammoth Cave National Park, KY

As September approaches, Mammoth Cave National Park enjoys significant weather changes that mark the onset of fall. Temperature and daylight hours decrease noticeably, carrying mild and shorter days. Rainfall sustains its rhythm, keeping the park nourished and preparing it for the shifting season. With a declining UV index, sun exposure becomes more comfortable, enhancing outdoor experiences. September bridges summer's vibrancy with autumn's tranquility, marking an appealing time for explorers and nature lovers.

Temperature

September is characterized by a mild reduction in the average high-temperature, from a tropical 86°F (30°C) in August to a warm 80.6°F (27°C). September nights in Mammoth Cave National Park bring a significant cooling from the heat of the day, with averages of 57.2°F (14°C).

Rainfall

In Mammoth Cave National Park, in September, during 8 rainfall days, 3.74" (95mm) of precipitation is typically accumulated. Throughout the year, there are 126 rainfall days, and 50.63" (1286mm) of precipitation is accumulated.

Daylight

The average length of the day in September is 12h and 25min.
On the first day of September in Mammoth Cave National Park, Kentucky, sunrise is at 6:15 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:39 am and sunset at 6:28 pm CDT.

Sunshine

The average sunshine in September is 8h.

UV index

The average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV radiation for average individuals.
Note: In September, the maximum UV index of 7 translates into these guidelines:
Refrain from overexposure. Fair-skinned individuals could burn in under 20 minutes. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.