September weather forecast
Colleyville, TX

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Weather in September

The first month of the autumn, September, is still a hot month in Colleyville, Texas, with an average temperature varying between 87.8°F (31°C) and 70.2°F (21.2°C).

Temperature

The arrival of September is marked by a minor reduction in average high-temperature, sliding from a torrid 96.1°F (35.6°C) in August to a tropical 87.8°F (31°C). Throughout the month of September, Colleyville sees a steady low-temperature average of 70.2°F (21.2°C).

Heat index

September's average heat index is estimated at a very hot 95°F (35°C). Incorporate extra safety measures to avoid heat exhaustion and heat cramps. Continuous activity could provoke heatstroke.
For clarity, heat index numbers account for light winds and areas under shade. Uninterrupted exposure to the sun may boost the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', reflects the blend of air temperature and relative humidity to give a temperature impression. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. An elevated level of relative humidity hinders evaporation, leading to decreased heat elimination from the body, inducing a sensation of excess heat. When heat uptake goes beyond the body's cooling mechanisms, there's a surge in body temperature, posing health risks.

Humidity

The average relative humidity in September in Colleyville is 62%.

Rainfall

In September, the rain falls for 11.5 days. Throughout September, 0.55" (14mm) of precipitation is accumulated. Throughout the year, in Colleyville, there are 97.1 rainfall days, and 8.66" (220mm) of precipitation is accumulated.

Snowfall

January, March through December are months without snowfall.

Daylight

In September, the average length of the day in Colleyville is 12h and 22min.
On the first day of September, sunrise is at 7:03 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:14 pm CDT.

Sunshine

The average sunshine in September is 8.5h.

UV index

In Colleyville, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for average individuals.
Note: A maximum daily UV index of 6 during September morphs into the following directions:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. Avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is most intense, and remember that not all shade structures provide full protection. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
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Frequently asked questions

How hot does it get in Colleyville in September?

In Colleyville, in September, the average high-temperature is 87.8°F (31°C), and the average low-temperature is 70.2°F (21.2°C). The average heat index (a.k.a. 'feels like', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in September is estimated at 95°F (35°C).

What is the average humidity in September in Colleyville?

In Colleyville, the average relative humidity in September is 62%.

How many days does it rain in September in Colleyville?

In Colleyville, Texas, during September, the rain falls for 11.5 days and regularly aggregates up to 0.55" (14mm) of precipitation.

When it does not snow in Colleyville?

January, March through December are months without snowfall in Colleyville.

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

In September, the average day length in Colleyville is 12h and 22min.

What time are sunrise and sunset in September in Colleyville?

On the first day of September in Colleyville, sunrise is at 7:03 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:14 pm CDT.

How many hours of sunshine does Colleyville have in September?

In Colleyville, the average sunshine duration in September is 8.5h.

What is the UV index reading in September in Colleyville?

The average daily maximum UV index in September in Colleyville, Texas, is 6. A UV Index estimate of 6 to 7 represents a high hazard to health 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
Colleyville, TX

Average temperature in September - Colleyville, TX
  • Average high temperature in September: 87.8°F

The warmest month (with the highest average high temperature) is August (96.1°F).
The month with the lowest average high temperature is January (54.5°F).

  • Average low temperature in September: 70.2°F

The month with the highest average low temperature is August (76.6°F).
The coldest month (with the lowest average low temperature) is January (39°F).

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Average pressure in September
Colleyville, TX

Average pressure in September - Colleyville, TX
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

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Average wind speed in September
Colleyville, TX

Average wind speed in September - Colleyville, TX
  • Average wind speed in September: 6.7mph

The windiest months (with the highest average wind speed) are March and April (10.1mph).
The calmest month (with the lowest average wind speed) is September (6.7mph).

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Average humidity in September
Colleyville, TX

Average humidity in September - Colleyville, TX
  • Average humidity in September: 62%

The month with the highest relative humidity is May (71%).
The month with the lowest relative humidity is August (54%).

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Average rainfall in September
Colleyville, TX

Average rainfall in September - Colleyville, TX
  • Average rainfall in September: 0.55"

The wettest month (with the highest rainfall) is May (1.26").
The driest month (with the least rainfall) is February (0.35").

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Average rainfall days in September
Colleyville, TX

Average rainfall days in September - Colleyville, TX
  • Average rainfall days in September: 11.5 days

The month with the highest number of rainy days is September (11.5 days).
The month with the least rainy days is January (4.7 days).

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Average snowfall in September
Colleyville, TX

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

The month with the highest snowfall is February (0.16").
The months with the least snowfall are January, March, April, May, June, July, August, September, October, November and December (0").

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Average snowfall days in September
Colleyville, TX

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

The month with the highest number of snowfall days is February (1.2 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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

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

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

  • Average sunshine in September: 8h and 3min

The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

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Average sunshine days in September
Colleyville, TX

Average sunshine days in September - Colleyville, TX
  • Average sunshine days in September: 16.3 days

The month with the most sunshine days is January (25.3 days).
The month with the least sunshine days is September (16.3 days).

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Average UV index in September
Colleyville, TX

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

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

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Average cloud cover in September
Colleyville, TX

Average cloud cover in September - Colleyville, TX
  • Average cloud cover in September: 28

The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is August (Cloud cover 19).

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Average visibility in September
Colleyville, TX

Average visibility in September - Colleyville, 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).

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Colleyville, Texas, USA

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