September is one of the warmer months of the year in Maryville, with average highs near 25.9°C and lows around 13.7°C (mean 19.8°C). It is one of the drier months, averaging 100 mm of rainfall and 72% relative humidity across the period.
September is one of the warmer months of the year in Maryville. Across 45 years of records, the warmest September in Maryville was 2019 — when the month averaged 24.1°C — while the coldest was 2001 at 17.6°C. Typical September days reach 25.9°C with nights near 13.7°C. The long-term trend is warming, about 0.4°C per decade.
September is one of the drier months in Maryville, averaging 100 mm of rainfall. The wettest September on record was 1989 with 263 mm, while the driest was 2019 at 10 mm.
Relative humidity in Maryville during September averages 72%. The most humid September was 1989 at 86%, and the least humid was 1999 at 51%.
September receives about 4.6 kWh/m²/day of solar energy in Maryville. The sunniest September was 2019 at 5.6 kWh/m²/day, and the cloudiest were 1988, 1992 and 2009 at 3.9.
Average wind speed in Maryville during September is 0.3 m/s. The windiest Septembers were 2022, 2024 and 2025, among others at 0.4 m/s, while the calmest were 2018, 2020 and 2023, among others at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.0°C | 19.7°C | 19.6°C | 20.7°C | 20.0°C | +1°C |
| Avg High | 25.1°C | 26.0°C | 25.8°C | 26.7°C | 25.9°C | +0.8°C |
| Avg Low | 12.8°C | 13.4°C | 13.4°C | 14.7°C | 14.1°C | +1.3°C |
| Avg Rain | 96 mm | 86 mm | 118 mm | 96 mm | 105 mm | +8 mm |
September temperatures in Maryville have risen by about 1.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 1.6°C (1993) to a record high of 35.2°C (1998).
Rainfall in September is one of the drier months, averaging 100 mm, with a wettest year of 263 mm.
One of the best times to visit Maryville
September is one of the best times to visit Maryville. Expect days averaging 25.9°C and nights around 13.7°C (mean 19.8°C) — warmer than Maryville's yearly average — with higher rainfall (100 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 | 26.0°C | 20.1°C | 14.2°C | 29.1°C | 9.2°C | 105 mm | 73% | 0.4 m/s | 4.7 |
| 2024 | 27.0°C | 21.2°C | 15.4°C | 31.8°C | 8.4°C | 195 mm | 71% | 0.4 m/s | 4.2 |
| 2023 | 27.2°C | 21.0°C | 14.7°C | 30.9°C | 9.8°C | 29 mm | 71% | 0.3 m/s | 5.1 |
| 2022 | 25.9°C | 19.3°C | 12.8°C | 32.5°C | 3.1°C | 78 mm | 71% | 0.4 m/s | 5 |
| 2021 | 24.3°C | 18.9°C | 13.6°C | 28.2°C | 5.6°C | 83 mm | 79% | 0.4 m/s | 4.9 |
| 2020 | 25.2°C | 19.4°C | 13.6°C | 30.1°C | 5.4°C | 137 mm | 79% | 0.3 m/s | 4.5 |
| 2019 🔥 | 31.1°C | 24.1°C | 17.1°C | 34.6°C | 13.3°C | 10 mm | 62% | 0.4 m/s | 5.6 |
| 2018 | 27.3°C | 22.5°C | 17.8°C | 30.8°C | 13.4°C | 158 mm | 81% | 0.3 m/s | 4.3 |
| 2017 | 25.1°C | 19.1°C | 13.1°C | 29.8°C | 6.8°C | 72 mm | 72% | 0.4 m/s | 4.8 |
| 2016 | 29.3°C | 22.8°C | 16.2°C | 32.8°C | 6.7°C | 41 mm | 63% | 0.4 m/s | 5.3 |
| 2015 | 26.1°C | 20.3°C | 14.4°C | 30.3°C | 6.0°C | 90 mm | 73% | 0.3 m/s | 4.6 |
| 2014 | 26.4°C | 20.5°C | 14.6°C | 30.5°C | 6.1°C | 76 mm | 77% | 0.3 m/s | 4.6 |
| 2013 | 24.6°C | 18.8°C | 13.1°C | 29.5°C | 6.3°C | 106 mm | 80% | 0.3 m/s | 4.8 |
| 2012 | 24.9°C | 18.9°C | 12.8°C | 32.1°C | 2.4°C | 126 mm | 75% | 0.3 m/s | 4.6 |
| 2011 | 24.7°C | 19.2°C | 13.7°C | 34.9°C | 7.9°C | 147 mm | 76% | 0.3 m/s | 4.3 |
| 2010 | 27.7°C | 21.0°C | 14.3°C | 33.4°C | 8.6°C | 130 mm | 67% | 0.3 m/s | 5.1 |
| 2009 | 24.2°C | 19.3°C | 14.5°C | 29.2°C | 5.5°C | 206 mm | 82% | 0.3 m/s | 3.9 |
| 2008 | 26.7°C | 20.2°C | 13.8°C | 30.8°C | 6.4°C | 36 mm | 71% | 0.3 m/s | 4.9 |
| 2007 | 28.8°C | 21.7°C | 14.5°C | 32.8°C | 6.8°C | 52 mm | 62% | 0.3 m/s | 5.2 |
| 2006 | 23.5°C | 17.8°C | 12.1°C | 27.9°C | 5.2°C | 144 mm | 79% | 0.3 m/s | 4.2 |
| 2005 | 28.1°C | 21.1°C | 14.1°C | 31.7°C | 8.8°C | 34 mm | 66% | 0.4 m/s | 5.4 |
| 2004 | 24.9°C | 19.0°C | 13.1°C | 30.4°C | 5.7°C | 229 mm | 80% | 0.3 m/s | 4.4 |
| 2003 | 24.1°C | 18.1°C | 12.2°C | 28.8°C | 3.6°C | 111 mm | 77% | 0.4 m/s | 4.9 |
| 2002 | 27.6°C | 21.4°C | 15.3°C | 33.5°C | 11.5°C | 170 mm | 73% | 0.3 m/s | 4.2 |
| 2001 ❄️ | 23.9°C | 17.6°C | 11.3°C | 29.3°C | 2.1°C | 99 mm | 70% | 0.4 m/s | 4.9 |
| 2000 | 26.3°C | 19.6°C | 12.8°C | 30.9°C | 2.7°C | 99 mm | 71% | 0.3 m/s | 4.4 |
| 1999 | 27.2°C | 19.8°C | 12.4°C | 32.6°C | 4.8°C | 56 mm | 51% | 0.4 m/s | 5.3 |
| 1998 | 30.0°C | 22.8°C | 15.6°C | 35.2°C | 7.3°C | 46 mm | 59% | 0.4 m/s | 5.1 |
| 1997 | 26.8°C | 20.2°C | 13.7°C | 32.4°C | 8.5°C | 122 mm | 66% | 0.4 m/s | 4.6 |
| 1996 | 24.1°C | 18.3°C | 12.5°C | 28.5°C | 4.7°C | 115 mm | 74% | 0.4 m/s | 4.4 |
| 1995 | 25.8°C | 19.5°C | 13.1°C | 30.7°C | 7.8°C | 76 mm | 74% | 0.3 m/s | 4.2 |
| 1994 | 24.1°C | 18.1°C | 12.2°C | 31.7°C | 5.9°C | 74 mm | 76% | 0.4 m/s | 4.7 |
| 1993 | 26.2°C | 19.8°C | 13.3°C | 32.4°C | 1.6°C | 107 mm | 69% | 0.4 m/s | 4.4 |
| 1992 | 24.9°C | 19.4°C | 13.8°C | 28.2°C | 2.7°C | 89 mm | 81% | 0.3 m/s | 3.9 |
| 1991 | 24.8°C | 19.2°C | 13.7°C | 30.8°C | 2.3°C | 72 mm | 76% | 0.3 m/s | 4.5 |
| 1990 | 26.5°C | 20.2°C | 13.9°C | 32.9°C | 2.3°C | 106 mm | 69% | 0.4 m/s | 4.8 |
| 1989 🌧️ | 23.6°C | 18.4°C | 13.2°C | 28.9°C | 4.2°C | 263 mm | 86% | 0.3 m/s | 4 |
| 1988 | 25.8°C | 19.6°C | 13.4°C | 29.8°C | 6.5°C | 107 mm | 77% | 0.3 m/s | 3.9 |
| 1987 | 25.2°C | 19.5°C | 13.8°C | 30.1°C | 9.1°C | 115 mm | 70% | 0.4 m/s | 4.3 |
| 1986 | 26.2°C | 20.5°C | 14.9°C | 29.5°C | 9.7°C | 76 mm | 77% | 0.3 m/s | 4.2 |
| 1985 | 26.0°C | 18.9°C | 11.8°C | 30.1°C | 4.1°C | 32 mm | 67% | 0.3 m/s | 4.9 |
| 1984 | 24.7°C | 17.9°C | 11.2°C | 30.2°C | 5.6°C | 20 mm | 67% | 0.4 m/s | 4.9 |
| 1983 | 25.1°C | 19.0°C | 12.9°C | 31.7°C | 2.1°C | 77 mm | 69% | 0.4 m/s | — |
| 1982 | 24.1°C | 18.2°C | 12.2°C | 29.5°C | 5.2°C | 76 mm | 76% | 0.3 m/s | — |
| 1981 | 25.4°C | 18.6°C | 11.8°C | 30.8°C | 5.1°C | 104 mm | 66% | 0.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 25.9°C with lows near 13.7°C (mean 19.8°C), based on 45 years of NASA POWER data.
September averages 100 mm of rainfall in Maryville, one of the drier months. The wettest on record was 263 mm in 1989.
The hottest September reached 35.2°C in 1998. The coldest dipped to 1.6°C in 1993.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.6°C. Daytime highs moved from 25.1°C to 26.1°C and overnight lows from 12°C to 14.1°C over the same span.
September is one of the warmer months of the year in Maryville and one of the drier months, so plan for around 25.9°C daytime highs and 13.7°C at night.
Not quite — September is the 9th coolest month in Maryville, averaging 19.8°C.
For September in Maryville, pack light layers you can adjust through the day, with typical highs of 25.9°C and lows of 13.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 72% — moderately humid.
Average wind speed in September is 0.3 m/s. The windiest September on record averaged 0.4 m/s (1981).
The wettest September on record was 1989 with 263 mm. On average, September sees 100 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 Maryville 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.
