September is one of the warmer months of the year in Arlington, with average highs near 32.7°C and lows around 20.1°C (mean 26.4°C). It is about average for rainfall, averaging 69 mm of rainfall and 61% relative humidity across the period.
September is one of the warmer months of the year in Arlington. Across 45 years of records, the warmest September in Arlington was 2019 — when the month averaged 30.9°C — while the coldest was 1991 at 23.3°C. Typical September days reach 32.7°C with nights near 20.1°C. The long-term trend is warming, about 0.4°C per decade.
September is about average for rainfall in Arlington, averaging 69 mm of rainfall. The wettest September on record was 2009 with 203 mm, while the driest was 2019 at 3 mm.
Relative humidity in Arlington during September averages 61%. The most humid September was 2018 at 79%, and the least humid was 2011 at 41%.
September receives about 5.3 kWh/m²/day of solar energy in Arlington. The sunniest September was 2011 at 6 kWh/m²/day, and the cloudiest was 2018 at 4.3.
Average wind speed in Arlington during September is 2.5 m/s. The windiest September was 1984 at 3.5 m/s, while the calmest were 2022 and 2025 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 25.9°C | 26.0°C | 25.7°C | 27.4°C | 27.2°C | +1.3°C |
| Avg High | 32.4°C | 32.3°C | 31.9°C | 33.5°C | 33.8°C | +1.4°C |
| Avg Low | 19.4°C | 19.7°C | 19.5°C | 21.3°C | 20.7°C | +1.3°C |
| Avg Rain | 67 mm | 69 mm | 71 mm | 75 mm | 61 mm | -5 mm |
September temperatures in Arlington have risen by about 1.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 5.5°C (1984) to a record high of 45.3°C (2000).
Rainfall in September is about average for rainfall, averaging 69 mm, with a wettest year of 203 mm.
One of the best times to visit Arlington
September is one of the best times to visit Arlington. Expect days averaging 32.7°C and nights around 20.1°C (mean 26.4°C) — warmer than Arlington's yearly average — with moderate rainfall (69 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 | 34.6°C | 27.6°C | 20.7°C | 40.1°C | 15.5°C | 38 mm | 55% | 1.9 m/s | 5.7 |
| 2024 | 33.4°C | 26.9°C | 20.3°C | 39.6°C | 13.1°C | 83 mm | 60% | 2.2 m/s | 5.4 |
| 2023 | 36.2°C | 29.6°C | 23.1°C | 45.0°C | 19.8°C | 50 mm | 53% | 2.3 m/s | 5.4 |
| 2022 | 33.4°C | 26.7°C | 20.1°C | 37.3°C | 12.7°C | 37 mm | 61% | 1.9 m/s | 5.9 |
| 2021 | 35.2°C | 28.0°C | 20.8°C | 39.6°C | 13.2°C | 24 mm | 51% | 2.2 m/s | 5.7 |
| 2020 | 29.9°C | 24.4°C | 18.9°C | 34.6°C | 10.4°C | 136 mm | 73% | 2.7 m/s | 4.5 |
| 2019 🔥 | 37.5°C | 30.9°C | 24.3°C | 40.5°C | 22.2°C | 3 mm | 53% | 2.9 m/s | 5.7 |
| 2018 | 30.4°C | 26.0°C | 21.6°C | 37.1°C | 13.8°C | 179 mm | 79% | 2 m/s | 4.3 |
| 2017 | 33.4°C | 26.8°C | 20.2°C | 37.4°C | 14.3°C | 31 mm | 61% | 2.6 m/s | 5.5 |
| 2016 | 32.1°C | 26.5°C | 20.9°C | 36.8°C | 11.4°C | 58 mm | 70% | 2.1 m/s | 5.4 |
| 2015 | 34.9°C | 28.4°C | 21.9°C | 39.6°C | 17.5°C | 29 mm | 55% | 2.3 m/s | 5.6 |
| 2014 | 32.9°C | 26.9°C | 20.9°C | 38.8°C | 13.7°C | 32 mm | 63% | 2.3 m/s | 5 |
| 2013 | 34.3°C | 28.3°C | 22.3°C | 40.7°C | 13.2°C | 97 mm | 55% | 2.2 m/s | 5.2 |
| 2012 | 33.4°C | 26.7°C | 19.9°C | 41.6°C | 13.2°C | 86 mm | 56% | 2.6 m/s | 5.3 |
| 2011 | 34.8°C | 27.3°C | 19.9°C | 42.9°C | 13.1°C | 35 mm | 41% | 2.6 m/s | 6 |
| 2010 | 31.2°C | 25.9°C | 20.6°C | 35.1°C | 10.6°C | 196 mm | 72% | 2.5 m/s | 5.3 |
| 2009 🌧️ | 29.1°C | 24.1°C | 19.2°C | 37.7°C | 12.1°C | 203 mm | 75% | 2.5 m/s | 4.4 |
| 2008 | 30.9°C | 24.6°C | 18.3°C | 35.0°C | 10.9°C | 50 mm | 68% | 2.4 m/s | 5.3 |
| 2007 | 30.0°C | 25.1°C | 20.2°C | 32.4°C | 16.2°C | 113 mm | 78% | 2 m/s | 5.1 |
| 2006 | 32.2°C | 25.3°C | 18.4°C | 37.7°C | 12.1°C | 51 mm | 58% | 2.7 m/s | 5.3 |
| 2005 | 36.2°C | 29.2°C | 22.3°C | 40.5°C | 16.8°C | 25 mm | 52% | 2.6 m/s | 5.6 |
| 2004 | 32.7°C | 26.0°C | 19.4°C | 36.6°C | 13.0°C | 24 mm | 60% | 2.1 m/s | 5.5 |
| 2003 | 30.0°C | 24.1°C | 18.1°C | 34.4°C | 12.8°C | 90 mm | 68% | 2.2 m/s | 5 |
| 2002 | 33.8°C | 27.1°C | 20.4°C | 38.5°C | 12.5°C | 46 mm | 58% | 2.5 m/s | 5.4 |
| 2001 | 29.4°C | 24.1°C | 18.7°C | 32.7°C | 10.4°C | 83 mm | 73% | 2.3 m/s | 5.4 |
| 2000 | 34.5°C | 27.3°C | 20.0°C | 45.3°C | 8.0°C | 26 mm | 47% | 2.7 m/s | 5.8 |
| 1999 | 33.2°C | 26.4°C | 19.5°C | 38.4°C | 10.2°C | 42 mm | 50% | 2.9 m/s | 5.6 |
| 1998 | 34.4°C | 28.6°C | 22.9°C | 43.5°C | 19.8°C | 95 mm | 64% | 2.5 m/s | 5 |
| 1997 | 35.3°C | 28.4°C | 21.5°C | 39.3°C | 14.4°C | 17 mm | 51% | 2.7 m/s | 5.5 |
| 1996 | 29.3°C | 23.7°C | 18.1°C | 33.4°C | 8.6°C | 78 mm | 72% | 2.1 m/s | 4.9 |
| 1995 | 31.9°C | 25.7°C | 19.5°C | 40.5°C | 7.4°C | 92 mm | 64% | 2.6 m/s | 4.7 |
| 1994 | 31.6°C | 24.8°C | 18.1°C | 36.6°C | 8.8°C | 63 mm | 63% | 2.4 m/s | 5 |
| 1993 | 32.9°C | 25.8°C | 18.7°C | 38.6°C | 9.4°C | 87 mm | 57% | 2.7 m/s | 5.5 |
| 1992 | 32.5°C | 25.9°C | 19.3°C | 36.3°C | 9.2°C | 72 mm | 65% | 2.9 m/s | 5.4 |
| 1991 ❄️ | 28.5°C | 23.3°C | 18.1°C | 32.6°C | 8.6°C | 86 mm | 75% | 2.3 m/s | 4.6 |
| 1990 | 33.3°C | 27.5°C | 21.7°C | 40.8°C | 10.2°C | 59 mm | 62% | 2.1 m/s | 4.9 |
| 1989 | 30.8°C | 24.1°C | 17.3°C | 40.1°C | 6.7°C | 69 mm | 61% | 2.5 m/s | 5.3 |
| 1988 | 33.3°C | 26.6°C | 19.8°C | 37.9°C | 14.1°C | 126 mm | 59% | 2.6 m/s | 5.1 |
| 1987 | 32.0°C | 25.4°C | 18.8°C | 36.7°C | 12.6°C | 67 mm | 63% | 2.4 m/s | 5.4 |
| 1986 | 31.7°C | 26.6°C | 21.5°C | 34.9°C | 15.6°C | 114 mm | 74% | 3.3 m/s | 4.8 |
| 1985 | 32.6°C | 26.3°C | 19.9°C | 42.6°C | 6.0°C | 92 mm | 57% | 3.3 m/s | 5.2 |
| 1984 | 32.2°C | 25.5°C | 18.7°C | 38.3°C | 5.5°C | 35 mm | 54% | 3.5 m/s | 5 |
| 1983 | 33.1°C | 26.3°C | 19.4°C | 36.9°C | 7.7°C | 23 mm | 60% | 3.1 m/s | — |
| 1982 | 33.6°C | 26.6°C | 19.7°C | 39.1°C | 9.6°C | 20 mm | 51% | 2.8 m/s | — |
| 1981 | 32.2°C | 25.7°C | 19.2°C | 35.5°C | 9.1°C | 56 mm | 62% | 2.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 32.7°C with lows near 20.1°C (mean 26.4°C), based on 45 years of NASA POWER data.
September averages 69 mm of rainfall in Arlington, about average for rainfall. The wettest on record was 203 mm in 2009.
The hottest September reached 45.3°C in 2000. The coldest dipped to 5.5°C in 1984.
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 32.7°C to 34.6°C and overnight lows from 19.4°C to 21°C over the same span.
September is one of the warmer months of the year in Arlington and about average for rainfall, so plan for around 32.7°C daytime highs and 20.1°C at night.
Not quite — September is the 9th coolest month in Arlington, averaging 26.4°C.
For September in Arlington, pack light, breathable clothing and sun protection, with typical highs of 32.7°C and lows of 20.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 61% — moderately humid.
Average wind speed in September is 2.5 m/s. The windiest September on record averaged 3.5 m/s (1984).
The wettest September on record was 2009 with 203 mm. On average, September sees 69 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 Arlington 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.
