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September Weather in Jacksonville, United States

Last updated: June 24, 2025

In Jacksonville, United States, the average temperature in September hovers around 17°C (63°F). During this time, temperatures can swing from a chilly 1°C (35°F) to a warm 36°C (98°F). Expect 42 mm (1.7 in) of precipitation spread over 5 days, with an average humidity of 66%.

September Temperature in Jacksonville

In September, in Jacksonville, the average temperature is 17°C (63°F). Maximum temperatures can reach 36°C (98°F), while minimums can drop as low as 1°C (35°F). Travelers should be prepared for a wide range of temperatures, ensuring they pack appropriately for both warm days and chilly nights.

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 17°C (63°F), with highs reaching up to 36°C (98°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec393943495664717063524438
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 42 mm (1.7 in) over a span of 5 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 42 mm (1.7 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec13114211794643148424590107
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 66%. With an average temperature of 17°C (63°F), this humidity feels like a warm embrace, making travel refreshing yet slightly muggy, perfect for leisurely strolls or picturesque outdoor explorations, but travelers should be prepared for occasional discomfort as they navigate the vibrant sights.

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 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%85%86%83%83%83%78%67%66%77%87%87%
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 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3468101110108642
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 Weather4°C (40°F)131 mm (5.2 inches)84%moderate
February Weather4°C (40°F)142 mm (5.6 inches)85%moderate
March Weather6°C (44°F)117 mm (4.6 inches)86%high
April Weather10°C (49°F)94 mm (3.7 inches)83%very high
May Weather13°C (56°F)64 mm (2.5 inches)83%very high
June Weather18°C (64°F)31 mm (1.2 inches)83%extreme
July Weather22°C (71°F)3 mm (0.1 inches)78%very high
August Weather21°C (71°F)8 mm (0.3 inches)67%very high
September Weather17°C (63°F)42 mm (1.7 inches)66%very high
October Weather11°C (52°F)45 mm (1.8 inches)77%high
November Weather7°C (44°F)90 mm (3.5 inches)87%moderate
December Weather3°C (38°F)107 mm (4.2 inches)87%low

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