September is one of the warmer months of the year in League City, with average highs near 30.4°C and lows around 23.8°C (mean 27.1°C). It is a relatively wet time of year, averaging 147 mm of rainfall and 75% relative humidity across the period.
September is one of the warmer months of the year in League City. Across 45 years of records, the warmest September in League City was 2023 — when the month averaged 30.5°C — while the coldest was 1983 at 25.1°C. Typical September days reach 30.4°C with nights near 23.8°C. The long-term trend is warming, about 0.4°C per decade.
September is a relatively wet time of year in League City, averaging 147 mm of rainfall. The wettest September on record was 2019 with 548 mm, while the driest was 1982 at 35 mm.
Relative humidity in League City during September averages 75%. The most humid September was 2018 at 85%, and the least humid was 2011 at 62%.
September receives about 5.1 kWh/m²/day of solar energy in League City. The sunniest Septembers were 1999 and 2011 at 5.8 kWh/m²/day, and the cloudiest was 2018 at 3.7.
Average wind speed in League City during September is 2.9 m/s. The windiest Septembers were 1998 and 2002 at 3.7 m/s, while the calmest were 1990, 2016 and 2022 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 26.3°C | 27.0°C | 26.8°C | 27.6°C | 28.2°C | +1.9°C |
| Avg High | 29.5°C | 30.3°C | 30.1°C | 30.7°C | 32.1°C | +2.6°C |
| Avg Low | 23.1°C | 23.7°C | 23.5°C | 24.4°C | 24.5°C | +1.4°C |
| Avg Rain | 129 mm | 143 mm | 143 mm | 202 mm | 98 mm | -31 mm |
September temperatures in League City have risen by about 2.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 12.9°C (1983) to a record high of 40.3°C (2000).
Rainfall in September is a relatively wet time of year, averaging 147 mm, with a wettest year of 548 mm.
A good time to visit League City
September is a good time to visit League City, with days averaging 30.4°C and nights around 23.8°C (mean 27.1°C, warmer than League City's yearly average) and higher rainfall. April and October 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 | 32.7°C | 28.7°C | 24.7°C | 35.0°C | 20.9°C | 74 mm | 68% | 2.5 m/s | 5.7 |
| 2024 | 32.0°C | 28.1°C | 24.2°C | 34.4°C | 19.4°C | 50 mm | 75% | 3 m/s | 5.1 |
| 2023 🔥 | 34.6°C | 30.5°C | 26.5°C | 38.7°C | 23.5°C | 74 mm | 66% | 2.6 m/s | 5.4 |
| 2022 | 31.9°C | 27.9°C | 23.9°C | 35.4°C | 16.1°C | 50 mm | 70% | 2.3 m/s | 5.7 |
| 2021 | 30.3°C | 26.9°C | 23.6°C | 33.6°C | 17.5°C | 219 mm | 77% | 2.7 m/s | 5.1 |
| 2020 | 30.8°C | 27.4°C | 24.0°C | 34.9°C | 16.1°C | 122 mm | 75% | 3.6 m/s | 4.6 |
| 2019 🌧️ | 32.3°C | 29.1°C | 25.9°C | 35.5°C | 24.4°C | 548 mm | 75% | 3.3 m/s | 5.3 |
| 2018 | 29.2°C | 27.1°C | 25.0°C | 32.0°C | 22.1°C | 458 mm | 85% | 2.5 m/s | 3.7 |
| 2017 | 29.3°C | 26.1°C | 22.9°C | 31.0°C | 17.9°C | 62 mm | 79% | 2.6 m/s | 5.6 |
| 2016 | 30.5°C | 27.8°C | 25.0°C | 32.8°C | 17.4°C | 98 mm | 80% | 2.3 m/s | 5.2 |
| 2015 | 29.7°C | 26.8°C | 23.9°C | 32.5°C | 18.5°C | 228 mm | 79% | 2.5 m/s | 5.2 |
| 2014 | 29.7°C | 27.0°C | 24.4°C | 33.5°C | 19.8°C | 164 mm | 82% | 2.8 m/s | 4.7 |
| 2013 | 31.2°C | 28.2°C | 25.1°C | 34.2°C | 19.8°C | 157 mm | 76% | 3.3 m/s | 5 |
| 2012 | 30.7°C | 27.1°C | 23.5°C | 34.4°C | 17.6°C | 103 mm | 75% | 2.8 m/s | 5.3 |
| 2011 | 33.1°C | 28.4°C | 23.7°C | 36.5°C | 18.8°C | 61 mm | 62% | 3.3 m/s | 5.8 |
| 2010 | 30.9°C | 27.9°C | 24.8°C | 32.9°C | 16.5°C | 136 mm | 75% | 2.9 m/s | 4.9 |
| 2009 | 29.9°C | 26.7°C | 23.5°C | 32.8°C | 20.0°C | 127 mm | 78% | 2.4 m/s | 4.1 |
| 2008 | 29.2°C | 25.7°C | 22.1°C | 33.7°C | 18.2°C | 163 mm | 76% | 3.6 m/s | 5.5 |
| 2007 | 29.5°C | 26.9°C | 24.3°C | 31.0°C | 20.5°C | 154 mm | 81% | 2.4 m/s | 5 |
| 2006 | 29.9°C | 26.5°C | 23.1°C | 31.9°C | 17.2°C | 115 mm | 76% | 2.9 m/s | 5.2 |
| 2005 | 32.8°C | 29.2°C | 25.6°C | 36.6°C | 22.3°C | 83 mm | 73% | 3.3 m/s | 5.2 |
| 2004 | 32.0°C | 28.2°C | 24.5°C | 35.6°C | 21.6°C | 41 mm | 69% | 2.7 m/s | 5.3 |
| 2003 | 28.2°C | 25.5°C | 22.8°C | 30.3°C | 16.2°C | 223 mm | 79% | 2.7 m/s | 4.9 |
| 2002 | 28.9°C | 26.2°C | 23.4°C | 32.1°C | 18.9°C | 245 mm | 82% | 3.7 m/s | 4.7 |
| 2001 | 28.5°C | 25.6°C | 22.8°C | 31.9°C | 14.9°C | 164 mm | 82% | 2.9 m/s | 5.4 |
| 2000 | 31.6°C | 27.5°C | 23.3°C | 40.3°C | 13.2°C | 114 mm | 69% | 3.5 m/s | 5.7 |
| 1999 | 31.6°C | 27.3°C | 23.1°C | 35.7°C | 16.6°C | 74 mm | 65% | 3 m/s | 5.8 |
| 1998 | 30.5°C | 27.9°C | 25.3°C | 34.5°C | 23.6°C | 316 mm | 82% | 3.7 m/s | 4.9 |
| 1997 | 31.4°C | 27.9°C | 24.5°C | 34.6°C | 18.5°C | 181 mm | 72% | 2.8 m/s | 5.3 |
| 1996 | 29.1°C | 26.2°C | 23.3°C | 31.7°C | 13.9°C | 206 mm | 78% | 2.4 m/s | 5.1 |
| 1995 | 31.8°C | 28.1°C | 24.4°C | 35.7°C | 15.0°C | 70 mm | 70% | 2.4 m/s | 5.5 |
| 1994 | 29.1°C | 25.7°C | 22.4°C | 31.7°C | 13.9°C | 105 mm | 75% | 2.5 m/s | 5.5 |
| 1993 | 32.1°C | 27.8°C | 23.5°C | 35.2°C | 16.4°C | 68 mm | 70% | 3.1 m/s | 5.4 |
| 1992 | 29.6°C | 26.7°C | 23.8°C | 31.6°C | 15.1°C | 83 mm | 77% | 3.2 m/s | 4.9 |
| 1991 | 27.9°C | 25.3°C | 22.6°C | 30.4°C | 14.4°C | 175 mm | 82% | 2.8 m/s | 4.8 |
| 1990 | 29.9°C | 27.0°C | 24.0°C | 34.3°C | 15.4°C | 154 mm | 76% | 2.3 m/s | 5 |
| 1989 | 29.5°C | 25.5°C | 21.6°C | 33.9°C | 13.7°C | 45 mm | 73% | 2.9 m/s | 5.5 |
| 1988 | 30.2°C | 26.7°C | 23.2°C | 32.8°C | 18.4°C | 150 mm | 76% | 3.2 m/s | 5 |
| 1987 | 29.9°C | 26.5°C | 23.1°C | 32.6°C | 17.3°C | 137 mm | 72% | 2.7 m/s | 5.3 |
| 1986 | 29.6°C | 27.4°C | 25.2°C | 30.9°C | 23.4°C | 145 mm | 82% | 3 m/s | 4.6 |
| 1985 | 29.9°C | 26.8°C | 23.7°C | 36.3°C | 13.5°C | 168 mm | 75% | 3.6 m/s | 5.2 |
| 1984 | 28.6°C | 25.5°C | 22.5°C | 31.6°C | 13.0°C | 123 mm | 76% | 3.6 m/s | 4.6 |
| 1983 ❄️ | 27.8°C | 25.1°C | 22.5°C | 31.5°C | 12.9°C | 272 mm | 81% | 3.1 m/s | — |
| 1982 | 31.4°C | 27.5°C | 23.7°C | 34.1°C | 16.3°C | 35 mm | 68% | 3.1 m/s | — |
| 1981 | 28.7°C | 25.6°C | 22.6°C | 31.5°C | 14.1°C | 82 mm | 77% | 2.6 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 30.4°C with lows near 23.8°C (mean 27.1°C), based on 45 years of NASA POWER data.
September averages 147 mm of rainfall in League City, a relatively wet time of year. The wettest on record was 548 mm in 2019.
The hottest September reached 40.3°C in 2000. The coldest dipped to 12.9°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.3°C. Daytime highs moved from 29.3°C to 32.3°C and overnight lows from 23°C to 24.6°C over the same span.
September is one of the warmer months of the year in League City and a relatively wet time of year, so plan for around 30.4°C daytime highs and 23.8°C at night.
Not quite — September is the 9th coolest month in League City, averaging 27.1°C.
For September in League City, pack light, breathable clothing and sun protection, with typical highs of 30.4°C and lows of 23.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 75% — quite humid.
Average wind speed in September is 2.9 m/s. The windiest September on record averaged 3.7 m/s (1998).
The wettest September on record was 2019 with 548 mm. On average, September sees 147 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 League City 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.
