September weather forecast
Austin, TX

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The beautiful Lady Bird Lake passing through the city skyscrapers of Austin city, Texas
The beautiful Lady Bird Lake passing through the city skyscrapers of Austin city, Texas

Weather in September

September in Austin witnesses a clear shift in weather patterns. The temperature marks a noticeable fall, and the precipitation increases to 2.52" across the month. This month characterizes a clear shift from the triad of summer months. September's relatively balanced weather serves as an announcement to the pleasant and cooler conditions that October brings.

Temperature

September's arrival in Austin comes with a mild decrease in the average high-temperature, moving subtly from a very hot 96.4°F in August to a hot 88.2°F. Austin encounters an average low-temperature of 70.9°F during September nights.

Heat index

For September, the heat index is evaluated at a torrid 100.4°F. Extra precautions are necessary, heat cramps and heat exhaustion are plausible outcomes. Extended activity could lead to heatstroke.
Records show heat index calculations are tailored for shaded regions and mild winds. Exposure to the direct sun might augment heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is a measure of how hot it feels when the actual air humidity is factored in. The effect is experienced differently by individuals, hinging on unique characteristics such as body mass, stature, and level of activity. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to 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.
In the face of high temperatures, the human body's reflex is to perspire, leveraging sweat evaporation for cooling. An elevated level of relative humidity hinders evaporation, leading to decreased heat elimination from the body, inducing a sensation of excess heat. When heat surpasses the body's release mechanisms, dehydration and overheating risks become pronounced.

Humidity

In September, the average relative humidity is 68%.

Rainfall

In Austin, Texas, in September, it is raining for 15.1 days, with typically 2.52" of accumulated precipitation. Throughout the year, there are 142.7 rainfall days, and 21.5" of precipitation is accumulated.

Snowfall

In Austin, snow does not fall in March through December.

Daylight

In Austin, the average length of the day in September is 12h and 20min.
On the first day of the month, sunrise is at 7:07 am and sunset at 7:54 pm. On the last day of September, in Austin, sunrise is at 7:23 am and sunset at 7:18 pm CDT.

Sunshine

In September, the average sunshine in Austin is 8.4h.

UV index

In September, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: An average maximum UV index of 6 in September leads to these recommendations:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Avoid direct sunlight between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Keep in mind that shade structures may not provide complete protection. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
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FAQ

How hot does it get in Austin in September?

An average high-temperature, in September, in Austin, is 88.2°F and the average low-temperature is 70.9°F. In September, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 100.4°F.

What is the average humidity in September in Austin?

In Austin, the average relative humidity in September is 68%.

How many days does it rain in September in Austin?

In September, in Austin, Texas, the rain falls for 15.1 days. Throughout September, 2.52" of precipitation is accumulated.

When it does not snow in Austin?

March through December are months without snowfall in Austin, Texas.

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

The average day length in September in Austin, Texas, is 12h and 20min.

When is the sunrise / sunset in September in Austin?

In September, on the first day of the month, sunrise is at 7:07 am and sunset at 7:54 pm. On the last day of the month, in Austin, Texas, sunrise is at 7:23 am and sunset at 7:18 pm CDT.

How long on average sun shines in September in Austin?

In September, the average sunshine duration in Austin, Texas, is 8.4h.

What is the UV index intensity in September in Austin?

In September, the average daily maximum UV index in Austin, Texas, is 6. A UV Index value of 6 to 7 symbolizes a high health threat from exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
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
Austin, TX

Average temperature in September - Austin, TX
  • Average high temperature in September: 88.2°F

The warmest month (with the highest average high temperature) is August (96.4°F).
The month with the lowest average high temperature is January (59.4°F).

  • Average low temperature in September: 70.9°F

The month with the highest average low temperature is August (75.4°F).
The coldest month (with the lowest average low temperature) is January (42.6°F).

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Average pressure in September
Austin, TX

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Austin, TX

Average wind speed in September - Austin, TX
  • Average wind speed in September: 6.2mph

The windiest month (with the highest average wind speed) is March (9.2mph).
The calmest month (with the lowest average wind speed) is September (6.2mph).

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Average humidity in September
Austin, TX

Average humidity in September - Austin, TX
  • Average humidity in September: 68%

The month with the highest relative humidity is May (75%).
The month with the lowest relative humidity is August (59%).

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Average rainfall in September
Austin, TX

Average rainfall in September - Austin, TX
  • Average rainfall in September: 2.52"

The wettest month (with the highest rainfall) is May (3.78").
The driest month (with the least rainfall) is February (0.91").

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Average rainfall days in September
Austin, TX

Average rainfall days in September - Austin, TX
  • Average rainfall days in September: 15.1 days

The month with the highest number of rainy days is May (16.2 days).
The month with the least rainy days is January (8.2 days).

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Average snowfall in September
Austin, TX

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

The month with the highest snowfall is January (0.4").
The months with the least snowfall are March, April, May, June, July, August, September, October, November and December (0").

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Average snowfall days in September
Austin, TX

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

The months with the highest number of snowfall days are January and February (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October and December (0 days).

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

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

The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).

  • Average sunshine in September: 8h and 2min

The months with the most sunshine are July and August (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).

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Average sunshine days in September
Austin, TX

Average sunshine days in September - Austin, TX
  • Average sunshine days in September: 12.5 days

The month with the most sunshine days is January (20.5 days).
The month with the least sunshine days is May (11.1 days).

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Average UV index in September
Austin, TX

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

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

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Average cloud cover in September
Austin, TX

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

The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is August (Cloud cover 24).

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Average visibility in September
Austin, TX

Average visibility in September - Austin, 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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Austin, Texas, USA

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