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September Weather in Gretna, United States

Last updated: June 24, 2025

In September, the average temperature in Gretna, United States hovers around 23°C (73°F), creating a pleasant backdrop for outdoor activities. However, be prepared for a temperature range that can drop to a chilly 7°C (45°F) or soar to a steamy 37°C (99°F). This month also sees 109 mm (4.3 in) of precipitation across 11 days, contributing to an average humidity level of 75%, perfect for those who enjoy a lush, vibrant environment.

September Temperature in Gretna

In September in Gretna, the average temperature is 23°C (73°F). Maximums can reach 37°C (99°F), while minimums can dip as low as 7°C (45°F). Be prepared for a range of weather conditions, making it an ideal time for travelers who enjoy both warmth and cooler evenings.

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

The chart illustrates September temperature patterns in Gretna, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Gretna, September typically has an average temperature of 23°C (73°F), with highs reaching up to 37°C (99°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec404550596875807873634843
Data source: Temperature data for Gretna 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 Gretna

In Gretna in September, the precipitation amount is 109 mm (4.3 in), occurring over a span of 11 days.

September Precipitation Trends in Gretna

The chart displays monthly precipitation patterns in Gretna, 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 Gretna, September typically receives around 109 mm (4.3 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec7511270130118946310510911078104
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Gretna

In Gretna in September, humidity is 75%. With an average temperature of 23°C (73°F), this humidity feels like a warm embrace, making travel slightly uncomfortable yet invigorating as the air wraps around you, creating a sense of walking through a lush, tropical paradise.

September Average Humidity in Gretna

This chart illustrates the average monthly humidity levels in Gretna, 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 Gretna is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%84%82%83%83%79%77%75%81%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Gretna

In Gretna 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 Gretna.

Maximum UV Index Levels in Gretna for September

The chart shows the monthly maximum UV Index (UVI) for Gretna 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 Gretna typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3679101110109753
Data source: Gretna 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 Gretna Compares to Other Months

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

This table compares monthly weather conditions in Gretna, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)75 mm (2.9 inches)84%moderate
February Weather7°C (45°F)112 mm (4.4 inches)84%high
March Weather10°C (50°F)70 mm (2.8 inches)84%high
April Weather15°C (60°F)130 mm (5.1 inches)82%very high
May Weather20°C (68°F)118 mm (4.6 inches)82%very high
June Weather24°C (75°F)94 mm (3.7 inches)83%extreme
July Weather27°C (81°F)63 mm (2.5 inches)79%very high
August Weather25°C (78°F)105 mm (4.1 inches)77%very high
September Weather23°C (73°F)109 mm (4.3 inches)75%very high
October Weather17°C (63°F)110 mm (4.3 inches)81%high
November Weather9°C (49°F)78 mm (3.1 inches)87%moderate
December Weather6°C (44°F)104 mm (4.1 inches)85%moderate

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