September weather forecast
Houston, TX

Share
A beautiful park in Root square overlooking the central business district of Houston, Texas, USA
A beautiful park in Root square overlooking the central business district of Houston, Texas, USA

Weather in September

The arrival of September sees the start of a much-awaited break from the intense summer heat in Houston. As autumn encroaches, the city begins the transition into a calmer, more relaxed atmosphere. September brings respite to Houston in the form of a decrease in temperatures and relative humidity, enhancing the appeal of outdoor activities. Ironically, the city experiences increased rainfall accounting to 4.49" (114mm), despite a decrease in temperature. This unexpected rain combined with cooler temperatures enhances the overall appeal of the city in September.

Temperature

The transition into September subtly indicates a reduction in the average high-temperature, down to a still hot 88.3°F (31.3°C) from August's tropical 94.3°F (34.6°C). In Houston, September is marked by an average low-temperature of 72.7°F (22.6°C).

Heat index

The heat index value during September is estimated at a scorching 104°F (40°C). Undertake special precautions, the probability of heat exhaustion and heat cramps is high. Prolonged activity may provoke heatstroke.
In the scope of the heat index, its values resonate with shade and light wind conditions. The heat index can potentially augment by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. The individual's impression of temperature can be affected by numerous factors such as metabolic variations, physical exertion, and attire. Consider the fact that direct sun exposure can influence how hot one feels, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
The process of perspiration is vital for the human body to get rid of excess warmth by allowing sweat to evaporate. With an abundance of moisture present in the air, the process of evaporation becomes less effective, and the body fails to cool down as it should, leading to the sensation of overheating. When the body's heat gain surpasses its removal capacity, body temperature starts to climb, leading to potential heat-related ailments.

Humidity

In September, the average relative humidity in Houston is 74%.

Rainfall

The month with the most rainfall is September, when the rain falls for 19.5 days and typically aggregates up to 4.49" (114mm) of precipitation.

Snowfall

In Houston, snow does not fall in February through November.

Daylight

In Houston, the average length of the day in September is 12h and 20min.
On the first day of the month, sunrise is at 6:59 am and sunset at 7:43 pm. On the last day of September, in Houston, sunrise is at 7:14 am and sunset at 7:07 pm CDT.

Sunshine

The average sunshine in September is 8.6h.

UV index

In Houston, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: The UV index of 6 during September translates into the following guidance:
Stick with precautions and abide by sun safety procedures. Evading sunburn is essential. UV radiation from the Sun is most intense between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
[Resources]

Frequently asked questions

How hot is it in Houston in September?

The high-temperature, in September, in Houston, is 88.3°F (31.3°C), while the low-temperature averages to 72.7°F (22.6°C). In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which combines relative humidity and air temperature, is estimated at 104°F (40°C).

What is the average humidity in September in Houston?

In Houston, the average relative humidity in September is 74%.

What is the rainiest month in Houston?

The month with the most rainfall in Houston, Texas, is September, when the rain falls for 19.5 days and typically aggregates up to 4.49" (114mm) of precipitation.

How many days does it rain in September in Houston?

In Houston, during September, the rain falls for 19.5 days and regularly aggregates up to 4.49" (114mm) of precipitation.

When it does not snow in Houston?

February through November are months without snowfall in Houston.

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

In September, the average day length in Houston is 12h and 20min.

What time are sunrise and sunset in September in Houston?

On the first day of September, sunrise is at 6:59 am and sunset at 7:43 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 7:07 pm CDT.

How many hours of sunshine does Houston have in September?

In Houston, Texas, the average sunshine duration in September is 8.6h.

How high is the UV index in September in Houston?

In Houston, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Houston, TX

Average temperature in September - Houston, TX
  • Average high temperature in September: 88.3°F

The warmest month (with the highest average high temperature) is August (94.3°F).
The month with the lowest average high temperature is January (61.3°F).

  • Average low temperature in September: 72.7°F

The month with the highest average low temperature is August (77.5°F).
The coldest month (with the lowest average low temperature) is January (46°F).

[Resources]

Average pressure in September
Houston, TX

Average pressure in September - Houston, TX
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

[Resources]

Average wind speed in September
Houston, TX

Average wind speed in September - Houston, TX
  • Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is April (8.6mph).
The calmest month (with the lowest average wind speed) is September (5.9mph).

[Resources]

Average humidity in September
Houston, TX

Average humidity in September - Houston, TX
  • Average humidity in September: 74%

The month with the highest relative humidity is February (78%).
The months with the lowest relative humidity are August and October (70%).

[Resources]

Average rainfall in September
Houston, TX

Average rainfall in September - Houston, TX
  • Average rainfall in September: 4.49"

The wettest month (with the highest rainfall) is September (4.49").
The driest month (with the least rainfall) is February (1.77").

[Resources]

Average rainfall days in September
Houston, TX

Average rainfall days in September - Houston, TX
  • Average rainfall days in September: 19.5 days

The month with the highest number of rainy days is September (19.5 days).
The month with the least rainy days is January (11.8 days).

[Resources]

Average snowfall in September
Houston, TX

Average snowfall in September - Houston, TX
  • Average snowfall in September: 0"

The month with the highest snowfall is December (0.08").
The months with the least snowfall are February, March, April, May, June, July, August, September, October and November (0").

[Resources]

Average snowfall days in September
Houston, TX

Average snowfall days in September - Houston, TX
  • Average snowfall days in September: 0 days

The months with the highest number of snowfall days are January and December (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October and November (0 days).

[Resources]

Average daylight in September /
Average sunshine in September
Houston, TX

Average daylight in September / Average sunshine in September - Houston, TX
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 4h and 48min).

[Resources]

Average sunshine days in September
Houston, TX

Average sunshine days in September - Houston, TX
  • Average sunshine days in September: 7.9 days

The month with the most sunshine days is January (16.3 days).
The month with the least sunshine days is September (7.9 days).

[Resources]

Average UV index in September
Houston, TX

Average UV index in September - Houston, TX
  • Average UV index in September: 6

The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

[Resources]

Average cloud cover in September
Houston, TX

Average cloud cover in September - Houston, TX
  • Average cloud cover in September: 32

The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 27).

[Resources]

Average visibility in September
Houston, TX

Average visibility in September - Houston, TX
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

[Resources]

Houston, Texas, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location