September is one of the cooler months of the year in Muswellbrook, with average highs near 20.4°C and lows around 7.4°C (mean 13.9°C). It is one of the drier months, averaging 46 mm of rainfall and 66% relative humidity across the period.
September is one of the cooler months of the year in Muswellbrook. Across 45 years of records, the warmest September in Muswellbrook was 2023 — when the month averaged 16.9°C — while the coldest was 1984 at 11.4°C. Typical September days reach 20.4°C with nights near 7.4°C. The long-term trend is warming, about 0.5°C per decade.
September is one of the drier months in Muswellbrook, averaging 46 mm of rainfall. The wettest September on record was 1995 with 107 mm, while the driest was 2017 at 1 mm.
Relative humidity in Muswellbrook during September averages 66%. The most humid September was 1998 at 84%, and the least humid was 2017 at 43%.
September receives about 5.1 kWh/m²/day of solar energy in Muswellbrook. The sunniest Septembers were 2012, 2017 and 2023, among others at 5.7 kWh/m²/day, and the cloudiest was 2022 at 4.3.
Average wind speed in Muswellbrook during September is 0.8 m/s. The windiest Septembers were 1996, 2003 and 2017, among others at 1 m/s, while the calmest were 2015, 2022 and 2023, among others at 0.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.2°C | 13.0°C | 14.5°C | 14.4°C | 14.6°C | +1.4°C |
| Avg High | 19.6°C | 19.1°C | 21.2°C | 21.1°C | 21.2°C | +1.6°C |
| Avg Low | 6.8°C | 6.9°C | 7.9°C | 7.8°C | 8.1°C | +1.3°C |
| Avg Rain | 50 mm | 60 mm | 43 mm | 37 mm | 38 mm | -12 mm |
September temperatures in Muswellbrook have risen by about 1.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -0.4°C (1992) to a record high of 33.5°C (2017).
Rainfall in September is one of the drier months, averaging 46 mm, with a wettest year of 107 mm.
A good time to visit Muswellbrook
September is a good time to visit Muswellbrook, with days averaging 20.4°C and nights around 7.4°C (mean 13.9°C, cooler than Muswellbrook's yearly average) and moderate rainfall. December and February 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 | 20.4°C | 14.1°C | 7.8°C | 27.3°C | 3.7°C | 30 mm | 71% | 0.8 m/s | 5.4 |
| 2024 | 22.1°C | 15.1°C | 8.1°C | 28.2°C | 3.5°C | 36 mm | 56% | 0.9 m/s | 5.2 |
| 2023 🔥 | 25.0°C | 16.9°C | 8.9°C | 31.9°C | 3.8°C | 14 mm | 51% | 0.7 m/s | 5.7 |
| 2022 | 17.3°C | 12.7°C | 8.1°C | 19.9°C | 4.0°C | 82 mm | 81% | 0.7 m/s | 4.3 |
| 2021 | 20.9°C | 14.0°C | 7.1°C | 26.2°C | 2.6°C | 32 mm | 63% | 0.8 m/s | 5.2 |
| 2020 | 21.2°C | 14.9°C | 8.5°C | 27.9°C | 2.8°C | 32 mm | 68% | 0.9 m/s | 5 |
| 2019 | 22.3°C | 15.1°C | 7.9°C | 29.6°C | 3.0°C | 41 mm | 56% | 0.8 m/s | 5.4 |
| 2018 | 21.2°C | 14.4°C | 7.6°C | 29.4°C | 3.6°C | 25 mm | 61% | 0.8 m/s | 5 |
| 2017 | 23.3°C | 15.5°C | 7.8°C | 33.5°C | 2.7°C | 1 mm | 43% | 1 m/s | 5.7 |
| 2016 | 18.9°C | 13.4°C | 7.9°C | 22.0°C | 3.8°C | 66 mm | 72% | 0.9 m/s | 4.4 |
| 2015 | 19.9°C | 13.5°C | 7.2°C | 26.3°C | 2.7°C | 27 mm | 68% | 0.7 m/s | 5 |
| 2014 | 19.9°C | 13.7°C | 7.5°C | 28.7°C | 3.4°C | 36 mm | 69% | 0.7 m/s | 5.3 |
| 2013 | 24.1°C | 16.8°C | 9.4°C | 30.3°C | 4.8°C | 28 mm | 55% | 0.8 m/s | 5.6 |
| 2012 | 22.3°C | 14.8°C | 7.3°C | 29.0°C | 1.6°C | 23 mm | 56% | 0.8 m/s | 5.7 |
| 2011 | 19.6°C | 13.3°C | 7.0°C | 26.2°C | 2.6°C | 86 mm | 70% | 0.8 m/s | 5.1 |
| 2010 | 19.7°C | 13.8°C | 7.9°C | 24.4°C | 3.5°C | 38 mm | 72% | 0.8 m/s | 4.8 |
| 2009 | 22.2°C | 15.4°C | 8.6°C | 28.6°C | 3.8°C | 37 mm | 59% | 0.9 m/s | 5.3 |
| 2008 | 20.0°C | 13.8°C | 7.6°C | 28.3°C | 3.1°C | 89 mm | 70% | 0.9 m/s | 5.2 |
| 2007 | 18.4°C | 12.7°C | 7.0°C | 23.6°C | 3.2°C | 20 mm | 73% | 0.8 m/s | 5.3 |
| 2006 | 21.9°C | 15.1°C | 8.3°C | 30.1°C | 4.8°C | 88 mm | 65% | 0.8 m/s | 5.1 |
| 2005 | 20.1°C | 13.8°C | 7.6°C | 27.6°C | 3.3°C | 61 mm | 67% | 0.8 m/s | 4.8 |
| 2004 | 21.1°C | 14.3°C | 7.6°C | 30.1°C | 0.6°C | 44 mm | 64% | 0.7 m/s | 5 |
| 2003 | 21.3°C | 14.2°C | 7.1°C | 32.5°C | 2.7°C | 6 mm | 55% | 1 m/s | 5.4 |
| 2002 | 22.6°C | 15.3°C | 8.0°C | 29.3°C | 3.7°C | 31 mm | 52% | 0.8 m/s | 5.2 |
| 2001 | 21.7°C | 15.1°C | 8.5°C | 28.9°C | 5.3°C | 24 mm | 67% | 0.7 m/s | 4.8 |
| 2000 | 22.9°C | 15.7°C | 8.5°C | 32.6°C | 3.5°C | 29 mm | 62% | 0.8 m/s | 5.3 |
| 1999 | 19.9°C | 14.1°C | 8.2°C | 26.6°C | 2.4°C | 71 mm | 73% | 0.7 m/s | 4.8 |
| 1998 | 18.7°C | 13.6°C | 8.6°C | 26.2°C | 2.1°C | 78 mm | 84% | 0.7 m/s | 4.5 |
| 1997 | 19.2°C | 13.5°C | 7.7°C | 24.2°C | 4.0°C | 71 mm | 72% | 0.8 m/s | 4.6 |
| 1996 | 19.0°C | 12.9°C | 6.7°C | 26.5°C | 2.9°C | 72 mm | 68% | 1 m/s | 5 |
| 1995 🌧️ | 19.3°C | 13.3°C | 7.2°C | 25.7°C | 0.7°C | 107 mm | 68% | 0.7 m/s | 4.5 |
| 1994 | 20.9°C | 13.2°C | 5.5°C | 25.6°C | 1.1°C | 5 mm | 50% | 0.9 m/s | 5.7 |
| 1993 | 18.2°C | 12.3°C | 6.5°C | 23.5°C | 0.9°C | 70 mm | 74% | 0.7 m/s | 4.8 |
| 1992 | 18.8°C | 12.1°C | 5.4°C | 26.7°C | -0.4°C | 38 mm | 63% | 0.8 m/s | 4.9 |
| 1991 | 20.6°C | 13.5°C | 6.4°C | 26.8°C | 0.7°C | 21 mm | 57% | 1 m/s | 5.5 |
| 1990 | 16.8°C | 11.7°C | 6.6°C | 22.9°C | 3.0°C | 68 mm | 82% | 0.7 m/s | 4.7 |
| 1989 | 17.9°C | 11.6°C | 5.3°C | 24.9°C | 0.3°C | 13 mm | 74% | 0.7 m/s | 5.5 |
| 1988 | 19.4°C | 13.8°C | 8.2°C | 24.6°C | 3.7°C | 94 mm | 75% | 0.8 m/s | 4.6 |
| 1987 | 20.1°C | 13.3°C | 6.4°C | 27.9°C | 0.2°C | 17 mm | 68% | 0.7 m/s | 5.5 |
| 1986 | 19.0°C | 13.2°C | 7.3°C | 26.6°C | 1.4°C | 78 mm | 74% | 0.7 m/s | 4.9 |
| 1985 | 18.0°C | 12.2°C | 6.4°C | 23.2°C | 2.1°C | 59 mm | 73% | 0.7 m/s | 5.2 |
| 1984 ❄️ | 17.8°C | 11.4°C | 5.0°C | 23.6°C | 1.3°C | 38 mm | 68% | 0.8 m/s | 4.9 |
| 1983 | 20.5°C | 14.1°C | 7.8°C | 28.1°C | 3.6°C | 47 mm | 70% | 0.9 m/s | — |
| 1982 | 20.5°C | 13.5°C | 6.6°C | 28.8°C | 1.6°C | 87 mm | 58% | 0.9 m/s | — |
| 1981 | 23.0°C | 15.5°C | 7.9°C | 30.5°C | 2.6°C | 17 mm | 59% | 0.8 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 20.4°C with lows near 7.4°C (mean 13.9°C), based on 45 years of NASA POWER data.
September averages 46 mm of rainfall in Muswellbrook, one of the drier months. The wettest on record was 107 mm in 1995.
The hottest September reached 33.5°C in 2017. The coldest dipped to -0.4°C in 1992.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.3°C. Daytime highs moved from 20°C to 21.1°C and overnight lows from 6.7°C to 8°C over the same span.
September is one of the cooler months of the year in Muswellbrook and one of the drier months, so plan for around 20.4°C daytime highs and 7.4°C at night.
Not quite — September is the 5th coolest month in Muswellbrook, averaging 13.9°C.
For September in Muswellbrook, pack warm layers and a jacket for chilly mornings, with typical highs of 20.4°C and lows of 7.4°C.
Relative humidity in September averages 66% — moderately humid.
Average wind speed in September is 0.8 m/s. The windiest September on record averaged 1 m/s (1991).
The wettest September on record was 1995 with 107 mm. On average, September sees 46 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 Muswellbrook 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.
