September is one of the warmer months of the year in Clarksville, with average highs near 28.9°C and lows around 15.8°C (mean 22.4°C). It is one of the drier months, averaging 86 mm of rainfall and 67% relative humidity across the period.
September is one of the warmer months of the year in Clarksville. Across 45 years of records, the warmest September in Clarksville was 2019 — when the month averaged 26.8°C — while the coldest were 2003 and 2006 at 20°C. Typical September days reach 28.9°C with nights near 15.8°C. The long-term trend is warming, about 0.3°C per decade.
September is one of the drier months in Clarksville, averaging 86 mm of rainfall. The wettest September on record was 2002 with 211 mm, while the driest was 2019 at 9 mm.
Relative humidity in Clarksville during September averages 67%. The most humid September was 2009 at 81%, and the least humid was 1999 at 40%.
September receives about 4.7 kWh/m²/day of solar energy in Clarksville. The sunniest September was 2019 at 5.5 kWh/m²/day, and the cloudiest were 1989 and 2009 at 4.
Average wind speed in Clarksville during September is 0.9 m/s. The windiest Septembers were 2008, 2010 and 2011, among others at 1 m/s, while the calmest were 2023 and 2025 at 0.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.8°C | 22.2°C | 22.2°C | 23.0°C | 22.4°C | +0.6°C |
| Avg High | 28.2°C | 29.1°C | 28.6°C | 29.5°C | 29.0°C | +0.8°C |
| Avg Low | 15.3°C | 15.3°C | 15.8°C | 16.5°C | 15.9°C | +0.6°C |
| Avg Rain | 86 mm | 80 mm | 101 mm | 75 mm | 91 mm | +4 mm |
September temperatures in Clarksville have risen by about 1.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 3.4°C (2001) to a record high of 38.9°C (1999).
Rainfall in September is one of the drier months, averaging 86 mm, with a wettest year of 211 mm.
One of the best times to visit Clarksville
September is one of the best times to visit Clarksville. Expect days averaging 28.9°C and nights around 15.8°C (mean 22.4°C) — warmer than Clarksville's yearly average — with higher rainfall (86 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 | 31.4°C | 23.9°C | 16.4°C | 36.0°C | 9.5°C | 86 mm | 61% | 0.7 m/s | 5 |
| 2024 | 30.2°C | 23.7°C | 17.1°C | 35.7°C | 9.1°C | 177 mm | 65% | 0.9 m/s | 4.4 |
| 2023 | 29.5°C | 22.7°C | 15.9°C | 33.6°C | 10.9°C | 57 mm | 67% | 0.7 m/s | 5.1 |
| 2022 | 28.8°C | 22.0°C | 15.3°C | 37.4°C | 7.2°C | 50 mm | 68% | 0.9 m/s | 5.2 |
| 2021 | 27.2°C | 21.4°C | 15.7°C | 32.0°C | 8.5°C | 92 mm | 77% | 0.8 m/s | 4.7 |
| 2020 | 26.6°C | 20.9°C | 15.1°C | 31.2°C | 8.3°C | 81 mm | 78% | 0.8 m/s | 4.4 |
| 2019 🔥 | 34.1°C | 26.8°C | 19.5°C | 37.4°C | 14.6°C | 9 mm | 60% | 0.8 m/s | 5.5 |
| 2018 | 30.2°C | 24.6°C | 19.1°C | 37.1°C | 12.2°C | 150 mm | 74% | 0.9 m/s | 4.2 |
| 2017 | 26.8°C | 21.0°C | 15.1°C | 32.0°C | 8.5°C | 83 mm | 75% | 0.9 m/s | 5 |
| 2016 | 29.5°C | 23.2°C | 17.0°C | 33.4°C | 9.6°C | 47 mm | 73% | 0.8 m/s | 5.2 |
| 2015 | 30.4°C | 23.5°C | 16.6°C | 36.4°C | 9.1°C | 44 mm | 65% | 0.8 m/s | 4.8 |
| 2014 | 29.5°C | 22.5°C | 15.5°C | 35.2°C | 8.1°C | 20 mm | 67% | 0.9 m/s | 4.8 |
| 2013 | 28.7°C | 22.5°C | 16.3°C | 33.9°C | 9.5°C | 102 mm | 74% | 0.8 m/s | 4.9 |
| 2012 | 27.3°C | 21.2°C | 15.2°C | 34.3°C | 5.1°C | 125 mm | 72% | 0.9 m/s | 4.6 |
| 2011 | 26.8°C | 20.8°C | 14.9°C | 38.6°C | 9.8°C | 140 mm | 69% | 1 m/s | 4.3 |
| 2010 | 31.3°C | 23.7°C | 16.0°C | 36.8°C | 9.4°C | 27 mm | 57% | 1 m/s | 5.2 |
| 2009 | 26.7°C | 21.8°C | 16.9°C | 30.7°C | 9.4°C | 154 mm | 81% | 0.8 m/s | 4 |
| 2008 | 30.4°C | 23.5°C | 16.7°C | 35.4°C | 11.2°C | 32 mm | 63% | 1 m/s | 4.6 |
| 2007 | 30.6°C | 24.1°C | 17.5°C | 36.7°C | 10.6°C | 86 mm | 63% | 0.8 m/s | 4.7 |
| 2006 | 26.1°C | 20.0°C | 13.9°C | 32.7°C | 7.0°C | 155 mm | 73% | 1 m/s | 4.4 |
| 2005 | 29.6°C | 23.2°C | 16.8°C | 33.7°C | 6.5°C | 51 mm | 71% | 0.8 m/s | 5.2 |
| 2004 | 28.8°C | 22.2°C | 15.6°C | 32.8°C | 9.2°C | 37 mm | 69% | 1 m/s | 4.9 |
| 2003 ❄️ | 25.9°C | 20.0°C | 14.1°C | 32.2°C | 4.7°C | 149 mm | 75% | 0.8 m/s | 5 |
| 2002 🌧️ | 30.5°C | 23.9°C | 17.4°C | 36.8°C | 8.7°C | 211 mm | 67% | 0.9 m/s | 4.5 |
| 2001 | 28.1°C | 21.2°C | 14.2°C | 34.5°C | 3.4°C | 60 mm | 66% | 1 m/s | 5 |
| 2000 | 28.8°C | 22.0°C | 15.2°C | 35.6°C | 5.3°C | 77 mm | 64% | 1 m/s | 4.5 |
| 1999 | 30.9°C | 22.8°C | 14.7°C | 38.9°C | 6.5°C | 29 mm | 40% | 1 m/s | 5.3 |
| 1998 | 33.2°C | 25.7°C | 18.2°C | 38.1°C | 10.3°C | 26 mm | 55% | 0.9 m/s | 5.2 |
| 1997 | 29.2°C | 22.1°C | 14.9°C | 35.2°C | 8.7°C | 74 mm | 63% | 0.9 m/s | 4.8 |
| 1996 | 27.0°C | 20.8°C | 14.6°C | 33.2°C | 7.4°C | 188 mm | 71% | 0.9 m/s | 4.6 |
| 1995 | 28.7°C | 21.5°C | 14.3°C | 34.2°C | 4.1°C | 58 mm | 61% | 0.9 m/s | 4.6 |
| 1994 | 28.2°C | 20.9°C | 13.5°C | 34.0°C | 8.5°C | 67 mm | 65% | 0.8 m/s | 4.7 |
| 1993 | 28.1°C | 21.4°C | 14.7°C | 34.3°C | 4.4°C | 92 mm | 67% | 1 m/s | 4.3 |
| 1992 | 27.5°C | 21.3°C | 15.0°C | 33.2°C | 4.4°C | 100 mm | 74% | 1 m/s | 4.2 |
| 1991 | 28.4°C | 22.3°C | 16.3°C | 35.4°C | 4.5°C | 71 mm | 68% | 0.9 m/s | 4.8 |
| 1990 | 30.3°C | 23.5°C | 16.7°C | 38.6°C | 6.1°C | 99 mm | 63% | 0.8 m/s | 4.7 |
| 1989 | 26.8°C | 21.0°C | 15.2°C | 34.0°C | 4.1°C | 116 mm | 76% | 0.9 m/s | 4 |
| 1988 | 28.6°C | 22.4°C | 16.2°C | 35.0°C | 7.7°C | 123 mm | 71% | 1 m/s | 4.2 |
| 1987 | 29.8°C | 22.9°C | 16.1°C | 34.2°C | 10.4°C | 72 mm | 59% | 0.9 m/s | 4.6 |
| 1986 | 29.8°C | 23.9°C | 18.0°C | 33.7°C | 12.0°C | 98 mm | 71% | 1 m/s | 4.5 |
| 1985 | 27.6°C | 21.0°C | 14.4°C | 32.6°C | 5.8°C | 105 mm | 67% | 1 m/s | 4.9 |
| 1984 | 28.0°C | 21.0°C | 13.9°C | 36.1°C | 5.8°C | 53 mm | 61% | 1 m/s | 4.4 |
| 1983 | 30.3°C | 23.3°C | 16.3°C | 37.2°C | 4.4°C | 32 mm | 56% | 1 m/s | — |
| 1982 | 25.9°C | 20.1°C | 14.2°C | 31.0°C | 5.1°C | 98 mm | 77% | 0.8 m/s | — |
| 1981 | 27.3°C | 20.3°C | 13.2°C | 32.7°C | 6.8°C | 81 mm | 66% | 0.9 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 28.9°C with lows near 15.8°C (mean 22.4°C), based on 45 years of NASA POWER data.
September averages 86 mm of rainfall in Clarksville, one of the drier months. The wettest on record was 211 mm in 2002.
The hottest September reached 38.9°C in 1999. The coldest dipped to 3.4°C in 2001.
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 27.8°C to 29.4°C and overnight lows from 14.4°C to 16.1°C over the same span.
September is one of the warmer months of the year in Clarksville and one of the drier months, so plan for around 28.9°C daytime highs and 15.8°C at night.
Not quite — September is the 9th coolest month in Clarksville, averaging 22.4°C.
For September in Clarksville, pack light layers you can adjust through the day, with typical highs of 28.9°C and lows of 15.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 67% — moderately humid.
Average wind speed in September is 0.9 m/s. The windiest September on record averaged 1 m/s (1983).
The wettest September on record was 2002 with 211 mm. On average, September sees 86 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 Clarksville 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.
