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September Weather in Knoxville, United States

Last updated: June 24, 2025

In September, the average temperature in Knoxville, United States hovers around 24°C (75°F). Expect a minimum of 8°C (47°F) and a maximum of 36°C (96°F), providing a diverse climate experience. Rainfall totals approximately 72 mm (2.8 in) spread across 7 days, with an average humidity level of 59%. Whether you’re exploring outdoor activities or enjoying the local culture, be prepared for a range of weather conditions!

September Temperature in Knoxville

In September in Knoxville, the average temperature is 24°C (75°F). The maximum can reach 36°C (96°F), while the minimum can drop to as low as 8°C (47°F). Pack accordingly for a mix of warm days and cooler nights during your travels.

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

The chart illustrates September temperature patterns in Knoxville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Knoxville, September typically has an average temperature of 24°C (75°F), with highs reaching up to 36°C (96°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec394353586876807874624945
Data source: Temperature data for Knoxville 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 Knoxville

In Knoxville in September, the total precipitation amount is 72 mm (2.8 in) over the course of 7 days.

September Precipitation Trends in Knoxville

The chart displays monthly precipitation patterns in Knoxville, 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 Knoxville, September typically receives around 72 mm (2.8 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec101142156154213114771167210796110
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Knoxville

In Knoxville in September humidity is 59%. With an average temperature of 24°C (75°F), this humidity feels like a warm embrace, making outdoor activities refreshing yet slightly sticky, perfect for leisurely strolls but reminding travelers to stay hydrated.

September Average Humidity in Knoxville

This chart illustrates the average monthly humidity levels in Knoxville, 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 Knoxville is approximately 59%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%79%77%78%82%81%75%61%59%69%82%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Knoxville

In Knoxville 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 Knoxville.

Maximum UV Index Levels in Knoxville for September

The chart shows the monthly maximum UV Index (UVI) for Knoxville 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 Knoxville typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109754
Data source: Knoxville 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 Knoxville Compares to Other Months

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

This table compares monthly weather conditions in Knoxville, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)101 mm (4.0 inches)82%moderate
February Weather6°C (43°F)142 mm (5.6 inches)79%high
March Weather11°C (53°F)156 mm (6.1 inches)77%very high
April Weather15°C (59°F)154 mm (6.1 inches)78%very high
May Weather20°C (69°F)213 mm (8.4 inches)82%extreme
June Weather25°C (77°F)114 mm (4.5 inches)81%extreme
July Weather27°C (80°F)77 mm (3.0 inches)75%extreme
August Weather26°C (78°F)116 mm (4.6 inches)61%very high
September Weather24°C (75°F)72 mm (2.8 inches)59%very high
October Weather17°C (62°F)107 mm (4.2 inches)69%high
November Weather9°C (49°F)96 mm (3.8 inches)82%moderate
December Weather7°C (45°F)110 mm (4.3 inches)87%moderate

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