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September Weather in Houston, United States

Last updated: June 24, 2025

In September, the average temperature in Houston, United States hovers around 25°C (77°F). Expect a range where the minimum can drop to 10°C (51°F) and the maximum can soar up to 38°C (100°F). Be prepared for some rain, as 92 mm (3.6 in) of precipitation typically falls over about 8 days. With an average humidity level of 74%, it's sure to feel quite warm and sticky!

September Temperature in Houston

In September in Houston, the average temperature is 25°C (77°F). The maximum can reach 38°C (100°F), and the minimum can be as low as 10°C (51°F). This makes it a great time for travelers to enjoy warm days while still having cooler evenings for comfortable exploration.

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

The chart illustrates September temperature patterns in Houston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Houston, September typically has an average temperature of 25°C (77°F), with highs reaching up to 38°C (100°F) and lows dropping to around 10°C (51°F).
JanFebMarAprMayJunJulAugSepOctNovDec455057627278818077665249
Data source: Temperature data for Houston 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 Houston

In Houston in September, the precipitation amount is 92 mm (3.6 in), occurring over the course of 8 days.

September Precipitation Trends in Houston

The chart displays monthly precipitation patterns in Houston, 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 Houston, September typically receives around 92 mm (3.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec1281871631531201311031279211375138
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Houston

In Houston in September humidity is 74%. With an average temperature of 25°C (77°F), this humidity feels like a warm, muggy blanket wrapping around you, making travel a bit more challenging as you find yourself sticky and in need of frequent breaks to hydrate and cool down.

September Average Humidity in Houston

This chart illustrates the average monthly humidity levels in Houston, 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 Houston is approximately 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%82%82%82%79%82%77%74%73%85%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Houston

In Houston 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 Houston.

Maximum UV Index Levels in Houston for September

The chart shows the monthly maximum UV Index (UVI) for Houston 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 Houston typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec47810111111109764
Data source: Houston 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 Houston Compares to Other Months

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

This table compares monthly weather conditions in Houston, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather7°C (45°F)128 mm (5.0 inches)85%moderate
February Weather10°C (50°F)187 mm (7.4 inches)84%high
March Weather14°C (58°F)163 mm (6.4 inches)82%very high
April Weather17°C (63°F)153 mm (6.0 inches)82%very high
May Weather22°C (73°F)120 mm (4.7 inches)82%extreme
June Weather26°C (79°F)131 mm (5.2 inches)79%extreme
July Weather27°C (82°F)103 mm (4.1 inches)82%extreme
August Weather27°C (81°F)127 mm (5.0 inches)77%very high
September Weather25°C (77°F)92 mm (3.6 inches)74%very high
October Weather19°C (66°F)113 mm (4.4 inches)73%high
November Weather11°C (52°F)75 mm (3.0 inches)85%high
December Weather9°C (49°F)138 mm (5.4 inches)88%moderate

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