September is one of the warmer months of the year in Baytown, with average highs near 32°C and lows around 21.6°C (mean 26.8°C). It is a relatively wet time of year, averaging 122 mm of rainfall and 75% relative humidity across the period.
September is one of the warmer months of the year in Baytown. Across 45 years of records, the warmest September in Baytown was 2023 — when the month averaged 30.6°C — while the coldest was 1983 at 24.2°C. Typical September days reach 32°C with nights near 21.6°C. The long-term trend is warming, about 0.5°C per decade.
September is a relatively wet time of year in Baytown, averaging 122 mm of rainfall. The wettest September on record was 2019 with 355 mm, while the driest was 1982 at 36 mm.
Relative humidity in Baytown during September averages 75%. The most humid September was 2018 at 86%, and the least humid was 2011 at 59%.
September receives about 5.1 kWh/m²/day of solar energy in Baytown. The sunniest September was 2017 at 5.8 kWh/m²/day, and the cloudiest was 2018 at 3.8.
Average wind speed in Baytown during September is 1.4 m/s. The windiest September was 1998 at 1.8 m/s, while the calmest were 2007, 2016 and 2022, among others at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 26.0°C | 26.6°C | 26.4°C | 27.3°C | 28.1°C | +2.1°C |
| Avg High | 31.1°C | 31.8°C | 31.4°C | 32.3°C | 34.1°C | +3°C |
| Avg Low | 20.8°C | 21.4°C | 21.2°C | 22.3°C | 22.2°C | +1.4°C |
| Avg Rain | 109 mm | 126 mm | 126 mm | 148 mm | 82 mm | -27 mm |
September temperatures in Baytown have risen by about 2.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 8.1°C (1983) to a record high of 44.1°C (2000).
Rainfall in September is a relatively wet time of year, averaging 122 mm, with a wettest year of 355 mm.
A good time to visit Baytown
September is a good time to visit Baytown, with days averaging 32°C and nights around 21.6°C (mean 26.8°C, warmer than Baytown's yearly average) and higher rainfall. October and April are marginally more temperate, but September still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 35.0°C | 28.6°C | 22.2°C | 37.7°C | 16.3°C | 47 mm | 67% | 1.2 m/s | 5.6 |
| 2024 | 34.2°C | 28.2°C | 22.2°C | 37.7°C | 16.6°C | 55 mm | 73% | 1.5 m/s | 5 |
| 2023 🔥 | 36.9°C | 30.6°C | 24.3°C | 42.7°C | 19.6°C | 74 mm | 64% | 1.3 m/s | 5.7 |
| 2022 | 33.9°C | 27.6°C | 21.4°C | 37.9°C | 12.7°C | 39 mm | 70% | 1.1 m/s | 5.6 |
| 2021 | 32.2°C | 26.7°C | 21.2°C | 36.8°C | 13.3°C | 147 mm | 76% | 1.4 m/s | 5.1 |
| 2020 | 32.3°C | 27.2°C | 22.1°C | 37.4°C | 11.9°C | 130 mm | 74% | 1.7 m/s | 4.6 |
| 2019 🌧️ | 34.3°C | 29.2°C | 24.1°C | 39.6°C | 21.9°C | 355 mm | 73% | 1.6 m/s | 5.3 |
| 2018 | 30.2°C | 26.8°C | 23.4°C | 33.9°C | 19.9°C | 278 mm | 86% | 1.2 m/s | 3.8 |
| 2017 | 30.0°C | 25.2°C | 20.4°C | 32.4°C | 14.3°C | 49 mm | 81% | 1.2 m/s | 5.8 |
| 2016 | 31.7°C | 27.3°C | 22.9°C | 34.9°C | 13.4°C | 83 mm | 81% | 1.1 m/s | 5.5 |
| 2015 | 31.5°C | 26.6°C | 21.7°C | 34.9°C | 14.1°C | 143 mm | 78% | 1.2 m/s | 5 |
| 2014 | 31.0°C | 26.7°C | 22.4°C | 35.8°C | 16.1°C | 143 mm | 81% | 1.3 m/s | 4.6 |
| 2013 | 33.1°C | 28.0°C | 22.9°C | 37.3°C | 16.5°C | 170 mm | 75% | 1.5 m/s | 4.9 |
| 2012 | 33.0°C | 27.1°C | 21.3°C | 37.6°C | 15.0°C | 88 mm | 73% | 1.4 m/s | 5.3 |
| 2011 | 35.5°C | 28.4°C | 21.2°C | 39.9°C | 14.5°C | 49 mm | 59% | 1.7 m/s | 5.7 |
| 2010 | 32.6°C | 27.6°C | 22.7°C | 35.2°C | 12.9°C | 118 mm | 75% | 1.4 m/s | 5.1 |
| 2009 | 31.3°C | 26.4°C | 21.5°C | 35.3°C | 16.0°C | 107 mm | 78% | 1.2 m/s | 4.1 |
| 2008 | 30.0°C | 24.9°C | 19.7°C | 35.7°C | 14.8°C | 191 mm | 77% | 1.7 m/s | 5.3 |
| 2007 | 31.0°C | 26.5°C | 22.0°C | 32.6°C | 17.6°C | 101 mm | 82% | 1.1 m/s | 5.1 |
| 2006 | 31.6°C | 26.1°C | 20.6°C | 34.3°C | 13.2°C | 95 mm | 74% | 1.4 m/s | 5.3 |
| 2005 | 35.0°C | 29.3°C | 23.6°C | 39.1°C | 19.5°C | 89 mm | 70% | 1.6 m/s | 5.2 |
| 2004 | 34.0°C | 28.1°C | 22.1°C | 38.6°C | 17.7°C | 38 mm | 68% | 1.3 m/s | 5.5 |
| 2003 | 28.7°C | 24.4°C | 20.1°C | 31.1°C | 12.1°C | 189 mm | 82% | 1.2 m/s | 5.1 |
| 2002 | 29.9°C | 25.7°C | 21.4°C | 34.0°C | 16.4°C | 196 mm | 82% | 1.7 m/s | 4.4 |
| 2001 | 29.1°C | 24.8°C | 20.5°C | 33.2°C | 10.6°C | 156 mm | 84% | 1.3 m/s | 5.3 |
| 2000 | 33.5°C | 27.3°C | 21.0°C | 44.1°C | 10.3°C | 101 mm | 65% | 1.7 m/s | 5.3 |
| 1999 | 33.4°C | 26.9°C | 20.4°C | 38.3°C | 12.1°C | 80 mm | 64% | 1.5 m/s | 5.6 |
| 1998 | 31.6°C | 27.6°C | 23.7°C | 37.6°C | 21.9°C | 299 mm | 82% | 1.8 m/s | 4.8 |
| 1997 | 33.4°C | 27.7°C | 22.1°C | 36.6°C | 15.2°C | 140 mm | 71% | 1.4 m/s | 5.3 |
| 1996 | 29.7°C | 25.2°C | 20.8°C | 32.6°C | 9.9°C | 212 mm | 81% | 1.2 m/s | 5 |
| 1995 | 33.5°C | 27.7°C | 21.9°C | 38.2°C | 11.8°C | 59 mm | 70% | 1.2 m/s | 5.5 |
| 1994 | 30.5°C | 25.3°C | 20.0°C | 34.2°C | 10.6°C | 86 mm | 75% | 1.2 m/s | 5.2 |
| 1993 | 34.2°C | 27.6°C | 21.0°C | 37.5°C | 12.1°C | 55 mm | 67% | 1.5 m/s | 5.4 |
| 1992 | 31.7°C | 26.7°C | 21.8°C | 34.8°C | 11.6°C | 73 mm | 75% | 1.5 m/s | 4.9 |
| 1991 | 28.6°C | 24.4°C | 20.3°C | 31.4°C | 10.8°C | 144 mm | 84% | 1.3 m/s | 4.9 |
| 1990 | 31.6°C | 26.8°C | 22.0°C | 37.0°C | 11.6°C | 114 mm | 76% | 1.1 m/s | 5.1 |
| 1989 | 31.4°C | 25.3°C | 19.2°C | 36.8°C | 10.6°C | 45 mm | 71% | 1.4 m/s | 5.6 |
| 1988 | 32.6°C | 26.9°C | 21.1°C | 35.8°C | 14.4°C | 97 mm | 73% | 1.6 m/s | 4.9 |
| 1987 | 31.5°C | 26.1°C | 20.7°C | 35.1°C | 14.0°C | 110 mm | 72% | 1.3 m/s | 5.1 |
| 1986 | 30.6°C | 27.0°C | 23.5°C | 33.1°C | 21.2°C | 148 mm | 84% | 1.4 m/s | 4.8 |
| 1985 | 31.7°C | 26.6°C | 21.5°C | 39.5°C | 11.7°C | 159 mm | 73% | 1.7 m/s | 5.1 |
| 1984 | 30.6°C | 25.4°C | 20.2°C | 34.8°C | 9.8°C | 90 mm | 73% | 1.7 m/s | 4.7 |
| 1983 ❄️ | 28.4°C | 24.2°C | 19.9°C | 32.8°C | 8.1°C | 222 mm | 84% | 1.4 m/s | — |
| 1982 | 33.7°C | 27.5°C | 21.4°C | 37.1°C | 12.4°C | 36 mm | 65% | 1.5 m/s | — |
| 1981 | 29.7°C | 24.8°C | 19.9°C | 32.6°C | 10.4°C | 73 mm | 79% | 1.2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 32°C with lows near 21.6°C (mean 26.8°C), based on 45 years of NASA POWER data.
September averages 122 mm of rainfall in Baytown, a relatively wet time of year. The wettest on record was 355 mm in 2019.
The hottest September reached 44.1°C in 2000. The coldest dipped to 8.1°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.6°C. Daytime highs moved from 30.8°C to 34.4°C and overnight lows from 20.6°C to 22.3°C over the same span.
September is one of the warmer months of the year in Baytown and a relatively wet time of year, so plan for around 32°C daytime highs and 21.6°C at night.
Not quite — September is the 9th coolest month in Baytown, averaging 26.8°C.
For September in Baytown, pack light, breathable clothing and sun protection, with typical highs of 32°C and lows of 21.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 75% — moderately humid.
Average wind speed in September is 1.4 m/s. The windiest September on record averaged 1.8 m/s (1998).
The wettest September on record was 2019 with 355 mm. On average, September sees 122 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 Baytown 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.
