Austin, TX weather in September
Austin is hot and humid in September, with some rain: highs average 91°F and nights drop to about 70°F. There are about 7 days with rain. Midday heat is the main thing to plan around.
- Normal high
- 91°F
- Normal low
- 70°F
- Wet days
- 7
- 3.5 in total
- Muggy days
- 18
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 95°F | 88°F |
| Normal low | 73°F | 66°F |
| Chance of a wet day | 23% | 22% |
| Sunrise / sunset | 7:07 am / 7:54 pm | 7:23 am / 7:18 pm |
| Daylight | 12.8 h | 11.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical September day
- 6 am70°Fdew point 64°F
- 9 am77°Fdew point 65°F
- Noon85°Fdew point 63°F
- 3 pm88°Fdew point 61°F
- 6 pm85°Fdew point 61°F
- 9 pm77°Fdew point 62°F
NOAA hourly normals (local standard time) from Robert Gray AAF (56 mi away); average wind 8 mph; clear or few clouds in 46% of daytime hours, mostly cloudy or overcast in 36%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F1 of 30
- Hot dayshigh 90°F or more20 of 30
- Muggy daysdaily mean dew point 65°F or more18 of 30
- Wet daysat least 0.01 in of rain or melted snow7 of 30
- Notable rainat least 0.10 in4 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 3.5 in; a dry September brings about 1.6 in and a wet one about 5.7 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202019: average high 100°F
- Coolest September1991: average high 87°F
- Wettest September2010: 13.2 in
- Driest September2008: 0.02 in
- Highest reading112°F (September 5, 2000)
- Lowest reading49°F (September 26, 2000)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 98°F | 91°F | 83°F |
| Normal low | 75°F | 70°F | 61°F |
| Wet days | 5 | 7 | 7 |
| Comfortable days | 0 | 1 | 6 |
| Daylight | 13.2 h | 12.3 h | 11.4 h |
Highs change by -7°F from August and -8°F into October.
How Austin ranks in September
- Normal high28th warmest of 378 cities; 6th of 38 in Texas
- Wet days158th driest of 378
- Comfortable days297th most of 342
What to pack for Austin in September
- Light, breathable clothing – highs near 91°F and about 18 muggy days
Heating and cooling
September has 1 heating degree days and 474 cooling degree days (base 65°F), 10% of the year's total heating and cooling demand.
Questions
How hot is Austin in September?
The normal high is 91°F and the normal low is 70°F. From 1991 to 2020 the hottest September reading was 112°F (September 5, 2000).
Does it rain a lot in Austin in September?
About 7 days in September have at least 0.01 in of precipitation, and the normal total is 3.5 in. The wettest September in 1991-2020 was in 2010 (13.2 in); the driest was in 2008 (0.02 in).
Is September a good time to visit Austin?
September ranks 10th of 12 months on our comfort score for Austin (37 out of 100). It has about 1 comfortable day and about 20 days at 90°F or hotter. The best months are February, March and November.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Austin-Camp Mabry (USW00013958), 3.9 mi NNW of the city center, 670 ft (183 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Robert Gray AAF (USW00003902), 56 mi N of the city center, 1,015 ft (528 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Austin-Camp Mabry (722544-13958), 3.9 mi NNW of the city center, 670 ft (183 ft higher than the city). Hourly observations, 1991-2020.