September Weather in Louisville, United States

Last updated: June 24, 2025

In September, the average temperature in Louisville, United States hovers around 25°C (77°F). Expect a range from a cool 10°C (50°F) to a scorching 37°C (99°F). During this month, the area experiences an average precipitation of 95 mm (3.7 in) over 8 days, contributing to a humidity level of 74%. Embrace the variety of weather conditions this lively destination has to offer!

September Temperature in Louisville

In September in Louisville, the average temperature is 25°C (77°F). Maximums can reach 37°C (99°F), while minimums can dip as low as 10°C (50°F). This makes it a perfect time for travelers to enjoy a variety of activities, from exploring the outdoors in the warm sun to experiencing cooler evenings.

September Weather in Louisville: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Louisville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Louisville, September typically has an average temperature of 25°C (77°F), with highs reaching up to 37°C (99°F) and lows dropping to around 10°C (50°F).

Data source: Temperature data for Louisville generated using information from the Copernicus Climate Change Service.

September Precipitation in Louisville

In Louisville in September, the total precipitation amount is 95 mm (3.7 in) spread over 8 days.

September Precipitation Trends in Louisville

The chart displays monthly precipitation patterns in Louisville, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Louisville, September typically receives around 95 mm (3.7 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Louisville

In Louisville in September humidity is 74%. With an average temperature of 25°C (77°F), this humidity feels like a warm, muggy blanket wrapping around you, making travel a bit more challenging as you find yourself sticky and in need of frequent breaks to hydrate and cool down.

September Average Humidity in Louisville

This chart illustrates the average monthly humidity levels in Louisville, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Louisville is approximately 74%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Louisville

In Louisville in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Louisville.

Maximum UV Index Levels in Louisville for September

The chart shows the monthly maximum UV Index (UVI) for Louisville in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Louisville typically reaches 9, which falls under the very high exposure category.

Data source: Louisville September UVI data generated using 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.

How September Weather in Louisville Compares to Other Months

Weather in Louisville varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Louisville, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Louisville, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	8°C (47°F)	110 mm (4.3 inches)	85%	moderate
February Weather	11°C (52°F)	181 mm (7.1 inches)	84%	high
March Weather	15°C (59°F)	130 mm (5.1 inches)	82%	very high
April Weather	17°C (64°F)	167 mm (6.6 inches)	82%	very high
May Weather	23°C (73°F)	127 mm (5.0 inches)	82%	extreme
June Weather	26°C (78°F)	164 mm (6.4 inches)	79%	extreme
July Weather	27°C (81°F)	120 mm (4.7 inches)	82%	extreme
August Weather	27°C (80°F)	130 mm (5.1 inches)	77%	extreme
September Weather	25°C (77°F)	95 mm (3.7 inches)	74%	very high
October Weather	20°C (68°F)	111 mm (4.4 inches)	73%	very high
November Weather	12°C (54°F)	67 mm (2.6 inches)	85%	high
December Weather	10°C (51°F)	120 mm (4.7 inches)	88%	moderate