Round Rock Weather in September
Average highs run from 83°F on September 1 to 73°F on September 30, and lows from 57°F to 46°F.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 79°F
- Average low
- 52°F
- Record high
- 96°FSep 6, 2020
- Record low
- 22°FSep 25, 2000
- Chance of a freeze
- 7%
- Daylight
- 12 h 57 min to 11 h 51 min
- Cloud cover
- 36%
- Humidity
- 40%
- Dew point
- 37°F
- Wind
- 7.6 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 83°F | 57°F | 92°F 2019 | 37°F 2010 | |
| Sep 2 | 83°F | 57°F | 91°F 2019 | 35°F 2020 | |
| Sep 3 | 82°F | 57°F | 92°F 2020 | 38°F 2020 | |
| Sep 4 | 82°F | 56°F | 95°F 2020 | 37°F 2008 | |
| Sep 5 | 82°F | 56°F | 93°F 2020 | 37°F 2004 | |
| Sep 6 | 82°F | 56°F | 96°F 2020 | 33°F 2004 | |
| Sep 7 | 82°F | 56°F | 93°F 2020 | 37°F 2008 | |
| Sep 8 | 81°F | 55°F | 92°F 2021 | 38°F 2001 | |
| Sep 9 | 81°F | 55°F | 93°F 2021 | 26°F 2001 | |
| Sep 10 | 81°F | 55°F | 91°F 2021 | 34°F 2001 | |
| Sep 11 | 81°F | 54°F | 89°F 2015 | 30°F 2020 | |
| Sep 12 | 80°F | 54°F | 90°F 2015 | 31°F 2020 | |
| Sep 13 | 80°F | 54°F | 88°F 2021 | 34°F 2019 | |
| Sep 14 | 80°F | 53°F | 88°F 2000 | 34°F 2005 | |
| Sep 15 | 79°F | 53°F | 87°F 2018 | 30°F 2005 | |
| Sep 16 | 79°F | 52°F | 86°F 2000 | 32°F 2005 | |
| Sep 17 | 79°F | 52°F | 87°F 2010 | 29°F 2006 | |
| Sep 18 | 78°F | 52°F | 88°F 2018 | 25°F 2006 | |
| Sep 19 | 78°F | 51°F | 87°F 2016 | 26°F 2006 | |
| Sep 20 | 77°F | 51°F | 88°F 2014 | 32°F 2002 | |
| Sep 21 | 77°F | 50°F | 85°F 2020 | 29°F 2021 | |
| Sep 22 | 77°F | 50°F | 83°F 2012 | 29°F 2004 | |
| Sep 23 | 76°F | 49°F | 84°F 2020 | 26°F 2009 | |
| Sep 24 | 76°F | 49°F | 87°F 2020 | 25°F 2006 | |
| Sep 25 | 76°F | 48°F | 86°F 2014 | 22°F 2000 | |
| Sep 26 | 75°F | 48°F | 86°F 2015 | 26°F 2017 | |
| Sep 27 | 75°F | 47°F | 87°F 2003 | 29°F 1998 | |
| Sep 28 | 74°F | 47°F | 86°F 2010 | 23°F 2013 | |
| Sep 29 | 74°F | 46°F | 86°F 2010 | 22°F 1999 | |
| Sep 30 | 73°F | 46°F | 86°F 2010 | 28°F 1999 |
Chance of rain
Sunrise and sunset
Times for 2026, local time (MDT).
- September 1
- sunrise 6:49 AM, sunset 7:46 PM
- September 30
- sunrise 7:12 AM, sunset 7:03 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00025129 (Lukachukai), public domain. Records: NOAA GHCN-Daily, station USW00003029, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.