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

September weather forecast and climate
Austin, TX

The beautiful Lady Bird Lake passing through the city skyscrapers of Austin city, Texas, in a beautiful sunrise panorama
The beautiful Lady Bird Lake passing through the city skyscrapers of Austin city, Texas, in a beautiful sunrise panorama
September, the first month of the autumn, in Austin, is still a tropical month, with average temperature fluctuating between 88.2°F (31.2°C) and 70.9°F (21.6°C).

Temperature

In Austin, Texas, the average high-temperature in September marginally drops, from a very hot 96.4°F (35.8°C) in August, to a tropical 88.2°F (31.2°C). In Austin, in September, the average low-temperature is 70.9°F (21.6°C).

Heat index

In September, the average heat index is evaluated at a very hot 99.5°F (37.5°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'felt air temperature', 'apparent temperature', or 'feels like', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (metabolic differences, clothing, differences in body mass, height, and shape). Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

The average relative humidity in September is 68%.

Rainfall

In September, the rain falls for 15.1 days. Throughout September, 2.52" (64mm) of precipitation is accumulated. Throughout the year, in Austin, there are 142.7 rainfall days, and 21.5" (546mm) of precipitation is accumulated.

Snowfall

March through December are months without snowfall in Austin.

Daylight

In Austin, the average length of the day is 12.3h.

Sunshine

The average sunshine in Austin is 8.4h.

UV index

In September, the average daily maximum UV index in Austin, Texas, is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from the exposure to the Sun's UV radiation for average individuals.
Note: The daily maximum UV index of 6 interpret into the following advice:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.

What is the temperature in September in Austin?

In Austin, in September, the average high-temperature is 88.2°F (31.2°C), and the average low-temperature is 70.9°F (21.6°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), that represents influence of the relative humidity to air temperaure, in September is appraised at 99.5°F (37.5°C).

What is the average humidity in September in Austin?

The average relative humidity in September in Austin, Texas, is 68%.

How many days does it rain in September in Austin?

In September, the rain falls for 15.1 days. Throughout September, 2.52" (64mm) of precipitation is accumulated.

When it does not snow in Austin?

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

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

In September, the average length of the day is 12.3h.

How many hours of sunshine does Austin have in September?

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

What is the UV index reading in September in Austin?

The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from the exposure to the Sun's UV rays.
Average temperature in September - Austin, TX
  • Average high temperature in September: 31.2°C

The warmest month (with the highest average high temperature) is August (35.8°C).
The month with the lowest average high temperature is January (15.2°C).

  • Average low temperature in September: 21.6°C

The month with the highest average low temperature is August (24.1°C).
The coldest month (with the lowest average low temperature) is January (5.9°C).

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%).

Average rainfall in September - Austin, TX
  • Average rainfall in September: 64mm

The wettest month (with the highest rainfall) is May (96mm).
The driest month (with the lowest rainfall) is February (23mm).

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 lowest number of rainy days is January (8.2 days).

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

The month with the highest snowfall is January (10.2mm).
Months with the lowest snowfall are March, April, May, June, July, August, September, October, November and December (0mm).

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

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

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

The month with the longest days is June (Average daylight: 14.1h).
The month with shortest days is December (Average daylight: 10.2h).

  • Average sunshine in September: 8.4h

Months with most sunshine are July and August (Average sunshine: 10.3h).
The month with least sunshine is December (Average sunshine: 5.3h).

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

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).