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September Weather in Louisville, United States

Last updated: June 24, 2025

In September, the average temperature in Louisville, United States hovers around 23°C (73°F). Temperature fluctuations can be significant, with a minimum dipping to 7°C (46°F) and a maximum soaring to 34°C (94°F). Expect some rain, as the area receives an average precipitation of 68 mm (2.7 in) over 6 days, accompanied by a consistent humidity level of 79%.

September Temperature in Louisville

In September in Louisville, the average temperature is 23°C (73°F), with maximums reaching 34°C (94°F) and minimums dropping as low as 7°C (46°F). This varied climate makes Louisville an ideal destination for travelers seeking both warm days and 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 23°C (73°F), with highs reaching up to 34°C (94°F) and lows dropping to around 7°C (46°F).
JanFebMarAprMayJunJulAugSepOctNovDec333647556877807673604439
Data source: Temperature data for Louisville generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Louisville

In Louisville in September, the precipitation amount is 68 mm (2.7 in) spread over the course of 6 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 68 mm (2.7 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec88981351211461119897681169385
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Louisville

In Louisville in September humidity is 79%. With an average temperature of 23°C (73°F), this humidity feels like a warm embrace that clings to the skin, making travel feel both invigorating and slightly exhausting as the air wraps around you like a damp blanket.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%84%83%80%83%82%83%79%79%88%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec357911111099643
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.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)88 mm (3.4 inches)84%moderate
February Weather2°C (36°F)98 mm (3.9 inches)82%moderate
March Weather8°C (47°F)135 mm (5.3 inches)84%high
April Weather13°C (56°F)121 mm (4.8 inches)83%very high
May Weather20°C (68°F)146 mm (5.7 inches)80%extreme
June Weather25°C (77°F)111 mm (4.4 inches)83%extreme
July Weather26°C (80°F)98 mm (3.8 inches)82%very high
August Weather25°C (77°F)97 mm (3.8 inches)82%very high
September Weather23°C (73°F)68 mm (2.7 inches)79%very high
October Weather15°C (60°F)116 mm (4.6 inches)79%high
November Weather7°C (44°F)93 mm (3.7 inches)88%moderate
December Weather4°C (39°F)85 mm (3.3 inches)87%moderate

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