Houston Weather in September

September's weather still feels hot at Houston, Texas. While the temperature has dropped from the previous months, afternoon humidity has climbed.

This page gives detailed information on the typical September weather for Houston.

You can jump directly to data and descriptions for:

The numbers here are historical averages based on climate data gathered at the George Bush Intercontinental Airport, located north of downtown Houston.

Temperature Weather iconTemperature

90 °F September average high 32 °C
70 °F September average low 21 °C

In most years, Houston averages a daily maximum temperature for September that's between 88 and 92 degrees Fahrenheit (31 to 33 degrees Celsius). The minimum temperature usually falls between 68 and 72 °F (20 to 22 °C).

The days at Houston begin to cool down quickly during September. By the end of the month, the temperature has dropped around 7 °F (4 °C) below what it was at the start.

17 days 90 °F max. or more (32 °C)
11 days 70 °F min. or less (21 °C)

Nearly every September day warms to over 80 °F (27 °C) in Houston. The city can reach 100 °F (38 °C) now, although days that hot don't happen this late every summer.

The thermometer dips to 60 °F (16 °C) or below on an average of 3 nights. But September does not normally get as cool as 50 °F (10 °C).

Rainy Weather iconRain

4.1 in total precipitation 105 mm
8 days of rain

Half the time, Houston receives 2 to 5 inches (40 to 123 mm) of rainfall in September. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

66 % sunshine
9 days clear skies

The sun's rays reach the ground in Houston during 66 percent of daylight hours on average in September, for a total of 244 hours in the month. Typically on 9 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in September at Houston lasts for 12 hours and 19 minutes a day on average. The longest day of the month is the 1st with 12 hours and 45 minutes of daylight. By the end of the month, the days have shortened to 11:53 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

77 % September average humidity

September is the most humid time of year for Houston. The relative humidity usually peaks at 93 percent in the morning then drops to 57 percent by mid afternoon.

Local Time12 am3 am6 am9 am12 pm3 pm6 pm9 pm
Humidity % 89 92 93 76 60 57 67 83

Windy Weather iconWind

6.5 mph September wind speed average 10.5 kph

September is less windy than most other months in Houston.

Stormy Weather iconStorms

2 days rainfall of 0.5 inches (13 mm) or more
8 days with thunderstorms in September
16 % chance a named storm approaches

There's a 6 percent probability that a hurricane will approach within 100 miles (165 km) of Houston during September. The chance of a major category 3 to 5 hurricane reaching the area is 1 percent.


These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

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