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September Weather in Jacksonville, United States

Last updated: June 24, 2025

In September, the average temperature in Jacksonville, United States hovers around 22°C (71°F), making it a delightful time to visit. Temperatures can vary significantly, dipping to a cool 6°C (43°F) at night and soaring to a balmy 34°C (94°F) during the day. Expect about 64 mm (2.5 in) of precipitation spread over 7 days, accompanied by an average humidity of 76%.

September Temperature in Jacksonville

In September in Jacksonville, the average temperature is 22°C (71°F). Maximums can reach 34°C (94°F), and minimums can be as low as 6°C (43°F). Be prepared for a range of temperatures if you plan to travel during this time, as it can be pleasantly warm during the day but cooler at night.

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

The chart illustrates September temperature patterns in Jacksonville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Jacksonville, September typically has an average temperature of 22°C (71°F), with highs reaching up to 34°C (94°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec293244536675787571574236
Data source: Temperature data for Jacksonville 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 Jacksonville

In Jacksonville in September, the precipitation amount is 64 mm (2.5 in) accumulated over a period of 7 days.

September Precipitation Trends in Jacksonville

The chart displays monthly precipitation patterns in Jacksonville, 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 Jacksonville, September typically receives around 64 mm (2.5 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec676413712315012310391641026648
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Jacksonville

In Jacksonville in September, humidity is 76%. With an average temperature of 22°C (71°F), this humidity feels like traveling through a warm, dense mist that clings to your skin, making every step feel heavier and the air seem thicker, which can be quite draining for outdoor activities.

September Average Humidity in Jacksonville

This chart illustrates the average monthly humidity levels in Jacksonville, 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 Jacksonville is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%80%80%80%82%83%81%80%76%76%85%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Jacksonville

In Jacksonville 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 Jacksonville.

Maximum UV Index Levels in Jacksonville for September

The chart shows the monthly maximum UV Index (UVI) for Jacksonville 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 Jacksonville typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910111199643
Data source: Jacksonville 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 Jacksonville Compares to Other Months

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

This table compares monthly weather conditions in Jacksonville, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)67 mm (2.6 inches)82%moderate
February Weather0°C (32°F)64 mm (2.5 inches)80%moderate
March Weather7°C (44°F)137 mm (5.4 inches)80%high
April Weather11°C (53°F)123 mm (4.8 inches)80%very high
May Weather19°C (66°F)150 mm (5.9 inches)82%very high
June Weather24°C (75°F)123 mm (4.9 inches)83%extreme
July Weather25°C (78°F)103 mm (4.0 inches)81%extreme
August Weather24°C (75°F)91 mm (3.6 inches)80%very high
September Weather22°C (71°F)64 mm (2.5 inches)76%very high
October Weather14°C (57°F)102 mm (4.0 inches)76%high
November Weather6°C (42°F)66 mm (2.6 inches)85%moderate
December Weather2°C (37°F)48 mm (1.9 inches)86%moderate

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