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September Weather in Galveston, United States

Last updated: June 24, 2025

In September, the average temperature in Galveston, United States hovers around 21°C (69°F), providing a pleasant climate for outdoor activities. However, prepare for temperature swings, as it can dip to a minimum of 5°C (41°F) and soar to a maximum of 33°C (92°F). Expect 67 mm (2.6 in) of precipitation spread over 8 days, with humidity levels averaging around 78%, creating a balmy atmosphere.

September Temperature in Galveston

In September in Galveston, the average temperature is 21°C (69°F). Maximum temperatures can reach 33°C (92°F), while minimums can drop to as low as 5°C (41°F). This diverse climate makes Galveston an ideal destination for travelers seeking both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Galveston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Galveston, September typically has an average temperature of 21°C (69°F), with highs reaching up to 33°C (92°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec293142516473767369574135
Data source: Temperature data for Galveston 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 Galveston

In Galveston in September, the total precipitation amount is 67 mm (2.6 in) over the course of 8 days.

September Precipitation Trends in Galveston

The chart displays monthly precipitation patterns in Galveston, 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 Galveston, September typically receives around 67 mm (2.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec76821049315210697101671057966
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Galveston

In Galveston in September, humidity is 78%. With an average temperature of 21°C (69°F), this humidity feels like a warm embrace that clings to your skin, making outdoor activities feel more intense and leaving you yearning for refreshing breezes or a cool drink as you explore.

September Average Humidity in Galveston

This chart illustrates the average monthly humidity levels in Galveston, 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 Galveston is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%86%87%81%82%81%79%78%81%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Galveston

In Galveston 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 Galveston.

Maximum UV Index Levels in Galveston for September

The chart shows the monthly maximum UV Index (UVI) for Galveston 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 Galveston typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910111098642
Data source: Galveston 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 Galveston Compares to Other Months

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

This table compares monthly weather conditions in Galveston, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)76 mm (3.0 inches)85%moderate
February Weather0°C (32°F)82 mm (3.2 inches)85%moderate
March Weather5°C (42°F)104 mm (4.1 inches)86%high
April Weather11°C (51°F)93 mm (3.7 inches)87%very high
May Weather18°C (64°F)152 mm (6.0 inches)81%very high
June Weather23°C (73°F)105 mm (4.2 inches)82%extreme
July Weather24°C (76°F)97 mm (3.8 inches)81%very high
August Weather23°C (74°F)101 mm (4.0 inches)79%very high
September Weather21°C (69°F)67 mm (2.6 inches)78%very high
October Weather14°C (57°F)105 mm (4.1 inches)81%high
November Weather5°C (41°F)79 mm (3.1 inches)89%moderate
December Weather2°C (35°F)66 mm (2.6 inches)86%low

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