September is one of the warmer months of the year in Dallas, with average highs near 29.6°C and lows around 16.5°C (mean 23.1°C). It is one of the drier months, averaging 91 mm of rainfall and 71% relative humidity across the period.
September is one of the warmer months of the year in Dallas. Across 45 years of records, the warmest September in Dallas was 2019 — when the month averaged 27.6°C — while the coldest was 1994 at 21°C. Typical September days reach 29.6°C with nights near 16.5°C. The long-term trend is warming, about 0.5°C per decade.
September is one of the drier months in Dallas, averaging 91 mm of rainfall. The wettest September on record was 2009 with 221 mm, while the driest was 1984 at 10 mm.
Relative humidity in Dallas during September averages 71%. The most humid September was 1992 at 84%, and the least humid was 1999 at 53%.
September receives about 4.7 kWh/m²/day of solar energy in Dallas. The sunniest September was 2019 at 5.8 kWh/m²/day, and the cloudiest were 1988 and 2002 at 3.8.
Average wind speed in Dallas during September is 0.1 m/s. The windiest Septembers were 2019, 2021 and 2023, among others at 0.2 m/s, while the calmest were 2022, 2024 and 2025, among others at 0.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.1°C | 22.9°C | 22.9°C | 24.2°C | 23.2°C | +1.1°C |
| Avg High | 28.5°C | 29.7°C | 29.3°C | 30.9°C | 29.6°C | +1.1°C |
| Avg Low | 15.7°C | 16.2°C | 16.4°C | 17.4°C | 16.8°C | +1.1°C |
| Avg Rain | 87 mm | 92 mm | 102 mm | 76 mm | 102 mm | +15 mm |
September temperatures in Dallas have risen by about 1.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 4.7°C (1983) to a record high of 38.9°C (2019).
Rainfall in September is one of the drier months, averaging 91 mm, with a wettest year of 221 mm.
One of the best times to visit Dallas
September is one of the best times to visit Dallas. Expect days averaging 29.6°C and nights around 16.5°C (mean 23.1°C) — warmer than Dallas's yearly average — with higher rainfall (91 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 31.7°C | 24.5°C | 17.4°C | 34.5°C | 13.1°C | 54 mm | 64% | 0.1 m/s | 5.2 |
| 2024 | 30.4°C | 24.3°C | 18.1°C | 36.6°C | 13.2°C | 207 mm | 69% | 0.1 m/s | 4.2 |
| 2023 | 30.6°C | 23.7°C | 16.8°C | 34.8°C | 11.1°C | 43 mm | 67% | 0.2 m/s | 5 |
| 2022 | 29.1°C | 22.3°C | 15.4°C | 35.7°C | 7.5°C | 73 mm | 70% | 0.1 m/s | 5.2 |
| 2021 | 27.9°C | 22.1°C | 16.2°C | 31.8°C | 7.8°C | 91 mm | 77% | 0.2 m/s | 4.8 |
| 2020 | 28.2°C | 22.4°C | 16.6°C | 34.6°C | 7.8°C | 143 mm | 76% | 0.1 m/s | 4.5 |
| 2019 🔥 | 35.4°C | 27.6°C | 19.7°C | 38.9°C | 14.0°C | 19 mm | 58% | 0.2 m/s | 5.8 |
| 2018 | 32.3°C | 26.2°C | 20.1°C | 36.0°C | 17.9°C | 83 mm | 73% | 0.1 m/s | 4.8 |
| 2017 | 28.8°C | 22.2°C | 15.7°C | 33.0°C | 9.6°C | 117 mm | 71% | 0.2 m/s | 5.3 |
| 2016 | 33.0°C | 25.9°C | 18.8°C | 36.9°C | 9.2°C | 46 mm | 63% | 0.1 m/s | 5.4 |
| 2015 | 29.3°C | 23.2°C | 17.1°C | 36.0°C | 8.9°C | 90 mm | 73% | 0.1 m/s | 4.4 |
| 2014 | 31.0°C | 24.5°C | 18.0°C | 35.3°C | 10.2°C | 50 mm | 71% | 0.1 m/s | 4.4 |
| 2013 | 28.6°C | 22.5°C | 16.3°C | 32.0°C | 11.1°C | 73 mm | 78% | 0.1 m/s | 4.9 |
| 2012 | 29.5°C | 22.6°C | 15.8°C | 36.1°C | 6.9°C | 96 mm | 71% | 0.1 m/s | 4.6 |
| 2011 | 28.1°C | 22.0°C | 15.8°C | 36.9°C | 11.5°C | 141 mm | 73% | 0.1 m/s | 4.5 |
| 2010 | 32.8°C | 25.0°C | 17.2°C | 36.3°C | 10.8°C | 49 mm | 61% | 0.1 m/s | 5.6 |
| 2009 🌧️ | 27.4°C | 22.6°C | 17.7°C | 31.6°C | 8.1°C | 221 mm | 82% | 0.1 m/s | 3.9 |
| 2008 | 30.0°C | 23.4°C | 16.8°C | 34.0°C | 9.3°C | 19 mm | 70% | 0.1 m/s | 4.9 |
| 2007 | 31.9°C | 24.6°C | 17.3°C | 36.2°C | 10.9°C | 52 mm | 63% | 0.1 m/s | 5 |
| 2006 | 29.1°C | 22.2°C | 15.3°C | 34.4°C | 7.9°C | 94 mm | 70% | 0.1 m/s | 4.8 |
| 2005 | 32.0°C | 24.5°C | 17.1°C | 35.5°C | 13.5°C | 20 mm | 65% | 0.1 m/s | 5.5 |
| 2004 | 27.2°C | 21.7°C | 16.2°C | 32.0°C | 9.3°C | 209 mm | 79% | 0.1 m/s | 4.4 |
| 2003 | 27.8°C | 21.5°C | 15.2°C | 32.5°C | 5.7°C | 55 mm | 76% | 0.1 m/s | 5 |
| 2002 | 30.6°C | 24.7°C | 18.8°C | 37.1°C | 15.1°C | 186 mm | 73% | 0.1 m/s | 3.8 |
| 2001 | 28.4°C | 21.5°C | 14.5°C | 33.4°C | 4.8°C | 71 mm | 69% | 0.1 m/s | 5 |
| 2000 | 28.6°C | 22.0°C | 15.5°C | 33.3°C | 5.9°C | 95 mm | 72% | 0.1 m/s | 4.2 |
| 1999 | 31.1°C | 22.9°C | 14.6°C | 37.1°C | 5.6°C | 38 mm | 53% | 0.1 m/s | 5 |
| 1998 | 32.2°C | 25.0°C | 17.8°C | 37.4°C | 10.5°C | 36 mm | 65% | 0.1 m/s | 4.7 |
| 1997 | 30.7°C | 23.8°C | 16.8°C | 35.8°C | 11.5°C | 158 mm | 66% | 0.2 m/s | 4.8 |
| 1996 | 28.2°C | 21.7°C | 15.2°C | 34.6°C | 8.3°C | 135 mm | 73% | 0.1 m/s | 4.4 |
| 1995 | 29.2°C | 22.6°C | 16.0°C | 34.8°C | 10.7°C | 101 mm | 74% | 0.1 m/s | 4.6 |
| 1994 ❄️ | 27.2°C | 21.0°C | 14.9°C | 31.8°C | 7.8°C | 119 mm | 78% | 0.1 m/s | 4.8 |
| 1993 | 31.2°C | 23.8°C | 16.5°C | 36.0°C | 5.8°C | 47 mm | 64% | 0.1 m/s | 4.9 |
| 1992 | 26.8°C | 21.7°C | 16.6°C | 30.9°C | 7.3°C | 110 mm | 84% | 0.1 m/s | 4 |
| 1991 | 28.7°C | 22.4°C | 16.1°C | 36.7°C | 5.8°C | 96 mm | 74% | 0.1 m/s | 4.9 |
| 1990 | 31.6°C | 24.3°C | 17.0°C | 37.9°C | 6.1°C | 83 mm | 64% | 0.2 m/s | 5.1 |
| 1989 | 26.6°C | 21.4°C | 16.3°C | 32.3°C | 9.4°C | 206 mm | 83% | 0.1 m/s | 3.9 |
| 1988 | 27.8°C | 22.2°C | 16.6°C | 32.3°C | 12.0°C | 161 mm | 80% | 0.1 m/s | 3.8 |
| 1987 | 29.8°C | 23.0°C | 16.3°C | 33.7°C | 9.8°C | 68 mm | 67% | 0.1 m/s | 4.5 |
| 1986 | 29.6°C | 23.8°C | 18.0°C | 34.5°C | 13.2°C | 70 mm | 77% | 0.1 m/s | 4.1 |
| 1985 | 28.7°C | 21.8°C | 14.9°C | 32.8°C | 6.1°C | 63 mm | 69% | 0.1 m/s | 5 |
| 1984 | 28.3°C | 21.2°C | 14.0°C | 34.9°C | 8.8°C | 10 mm | 67% | 0.1 m/s | 5.1 |
| 1983 | 27.4°C | 21.4°C | 15.4°C | 35.4°C | 4.7°C | 115 mm | 73% | 0.1 m/s | — |
| 1982 | 29.0°C | 22.1°C | 15.1°C | 34.1°C | 6.3°C | 40 mm | 68% | 0.1 m/s | — |
| 1981 | 29.5°C | 22.1°C | 14.7°C | 33.2°C | 7.5°C | 53 mm | 63% | 0.2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 29.6°C with lows near 16.5°C (mean 23.1°C), based on 45 years of NASA POWER data.
September averages 91 mm of rainfall in Dallas, one of the drier months. The wettest on record was 221 mm in 2009.
The hottest September reached 38.9°C in 2019. The coldest dipped to 4.7°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.7°C. Daytime highs moved from 28.6°C to 29.9°C and overnight lows from 14.8°C to 16.8°C over the same span.
September is one of the warmer months of the year in Dallas and one of the drier months, so plan for around 29.6°C daytime highs and 16.5°C at night.
Not quite — September is the 9th coolest month in Dallas, averaging 23.1°C.
For September in Dallas, pack light layers you can adjust through the day, with typical highs of 29.6°C and lows of 16.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 71% — moderately humid.
Average wind speed in September is 0.1 m/s. The windiest September on record averaged 0.2 m/s (1981).
The wettest September on record was 2009 with 221 mm. On average, September sees 91 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Dallas behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
