Houston
Texas, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Houston, TX

A beautiful park in Root square overlooking the central business district of Houston, Texas
A beautiful park in Root square overlooking the central business district of Houston, Texas
September extends the hot summer season of Houston with the average temperatures in the 70°F (21.1°C) to 90°F (32.2°C). The temperatures are mostly above 80.1°F (26.7°C) during the day, while an odd day heats up to 100°F (37.8°C). The heat usually decreases by the end of September, signaling the start of the autumn season.
The 12-hour days are mostly bright and sunny as the sunlight lasts for 8 hours. The rain gathers new momentum to register 4.1" (104.1mm).
Be careful, while stepping out on September afternoons in Houston, as the sun rays are intense.

What is the temperature in September in Houston?

In September, in Houston, the average high-temperature is 89.8°F (32.1°C), and the average low-temperature is 69.8°F (21°C).

What is the most humid month in Houston?

September is the most humid month in Houston, Texas, with an average relative humidity of 76.8%.

What is the average humidity in September in Houston?

In September, the average relative humidity in Houston is 76.8%.

How many days does it rain in September in Houston?

In September, in Houston, the rain falls for 8 days. Throughout September, 4.1" (104.6mm) of precipitation is accumulated.

What is the average length of the day in September in Houston?

The average length of the day in September in Houston, Texas, is 12.3h.

How long on average sun shines in September in Houston?

In Houston, Texas, the average sunshine in September is 7.9h.

What is the UV index intensity in September in Houston?

The average daily maximum UV index in September is 9. A UV Index reading of 8 to 10 represents a very high health risk from the exposure to the Sun's UV rays.
Average temperature in September - Houston, TX
  • Average high temperature in September: 89.7°F

The warmest month (with the highest average high temperature) is August (94.5°F).
The month with the lowest average high temperature is January (62.9°F).

  • Average low temperature in September: 69.8°F

The month with the highest average low temperature is July (75.1°F).
The coldest month (with the lowest average low temperature) is January (43.2°F).

Average humidity in September - Houston, TX
  • Average humidity in September: 76.8%

The month with the highest relative humidity is September (76.8%).
The month with the lowest relative humidity is March (72.7%).

Average rainfall in September - Houston, TX
  • Average rainfall in September: 4.1"

The wettest month (with the highest rainfall) is June (5.9").
The driest month (with the lowest rainfall) is February (3.2").

Average rainfall days in September - Houston, TX
  • Average rainfall days in September: 8 days

The month with the highest number of rainy days is June (10.6 days).
The month with the lowest number of rainy days is April (6.8 days).

Average daylight in September / Average sunshine in September - Houston, TX
  • Average daylight in September: 12.3h

The month with the longest days is June (Average daylight: 14h).
The month with shortest days is December (Average daylight: 10.3h).

  • Average sunshine in September: 7.9h

The month with most sunshine is July (Average sunshine: 9.5h).
The month with least sunshine is January (Average sunshine: 4.6h).

Average UV index in September - Houston, TX
  • Average UV index in September: 9

Months with the highest UV index are June and July (UV index 11).
Months with the lowest UV index are January and December (UV index 4).