September Weather in Louisville, United States

Last updated: June 24, 2025

In September, the average temperature in Louisville, United States reaches a warm 26°C (79°F). Expect a range where it can dip to a cool 12°C (54°F) at night and peak at a scorching 38°C (102°F) during the day. Be prepared for 83 mm (3.3 in) of rainfall spread over about 8 days, while the humidity remains notably high at 82%. 🌦️

September Temperature in Louisville

In September in Louisville, the average temperature is 26°C (79°F). Maximum temperatures can reach as high as 38°C (102°F), while minimums can drop as low as 12°C (54°F). Be prepared for a warm climate, with occasional fluctuations in temperature during your travels.

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 26°C (79°F), with highs reaching up to 38°C (102°F) and lows dropping to around 12°C (54°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 precipitation amount reaches 83 mm (3.3 in) over the course of 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 83 mm (3.3 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 82%. With an average temperature of 26°C (79°F), this humidity feels like a warm blanket that envelops you, making outdoor activities feel more taxing and requiring frequent breaks to stay hydrated.

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 82%, 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	10°C (50°F)	89 mm (3.5 inches)	86%	moderate
February Weather	13°C (55°F)	116 mm (4.6 inches)	84%	high
March Weather	15°C (60°F)	70 mm (2.8 inches)	83%	very high
April Weather	19°C (67°F)	99 mm (3.9 inches)	81%	very high
May Weather	24°C (75°F)	95 mm (3.7 inches)	81%	extreme
June Weather	27°C (80°F)	119 mm (4.7 inches)	81%	extreme
July Weather	28°C (83°F)	109 mm (4.3 inches)	83%	extreme
August Weather	28°C (82°F)	108 mm (4.3 inches)	81%	extreme
September Weather	26°C (79°F)	83 mm (3.3 inches)	82%	very high
October Weather	21°C (70°F)	97 mm (3.8 inches)	78%	very high
November Weather	13°C (56°F)	55 mm (2.2 inches)	86%	high
December Weather	11°C (52°F)	112 mm (4.4 inches)	89%	moderate