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 temperature, precipitation, sun, humidity, wind and storms for Houston. The numbers here are historical averages based on temperature and rainfall measurements gathered at Houston Hobby Airport and other climate data from George Bush Intercontinental Airport.

Temperature Weather iconTemperature

89 °F September average high 32 °C
73 °F September average low 23 °C
16 days 90 °F max. or more (32 °C)
7 days 70 °F min. or less (21 °C)

Nearly every September day warms to over 80 degrees Fahrenheit (27 degrees Celsius) 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 1 night during the month.

Rainy Weather iconRain

5.8 in total precipitation 146 mm
10 days of rain

Half the time, Houston receives 3.2 to 8.5 inches (81 to 215 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

3 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.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

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