September is one of the cooler months of the year in Bunbury, with average highs near 17.4°C and lows around 9.5°C (mean 13.5°C). It is a relatively wet time of year, averaging 86 mm of rainfall and 80% relative humidity across the period.
September is one of the cooler months of the year in Bunbury. Across 45 years of records, the warmest September in Bunbury was 2023 — when the month averaged 14.9°C — while the coldest was 2016 at 11.5°C. Typical September days reach 17.4°C with nights near 9.5°C. The long-term September temperature trend is broadly flat.
September is a relatively wet time of year in Bunbury, averaging 86 mm of rainfall. The wettest September on record was 2013 with 194 mm, while the driest was 2019 at 26 mm.
Relative humidity in Bunbury during September averages 80%. The most humid September was 1997 at 84%, and the least humid was 2010 at 74%.
September receives about 4.4 kWh/m²/day of solar energy in Bunbury. The sunniest September was 2024 at 4.9 kWh/m²/day, and the cloudiest were 2001, 2007 and 2013 at 3.9.
Average wind speed in Bunbury during September is 3.5 m/s. The windiest September was 2013 at 4.5 m/s, while the calmest were 1990, 1995 and 2004, among others at 3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.6°C | 13.1°C | 13.1°C | 13.6°C | 14.0°C | +0.4°C |
| Avg High | 17.7°C | 16.9°C | 16.7°C | 17.7°C | 18.2°C | +0.5°C |
| Avg Low | 9.5°C | 9.2°C | 9.5°C | 9.4°C | 9.9°C | +0.4°C |
| Avg Rain | 82 mm | 99 mm | 95 mm | 81 mm | 63 mm | -19 mm |
September temperatures in Bunbury have risen by about 0.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 3°C (1985) to a record high of 27°C (2023).
Rainfall in September is a relatively wet time of year, averaging 86 mm, with a wettest year of 194 mm.
A quieter season to visit Bunbury
If your dates are flexible, the more temperate months of March and December tend to be the most comfortable for visiting Bunbury. That said, September — with days averaging 17.4°C and nights around 9.5°C (mean 13.5°C) and higher rainfall (86 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 17.9°C | 13.8°C | 9.7°C | 23.8°C | 5.9°C | 81 mm | 80% | 3.1 m/s | 4.7 |
| 2024 | 18.6°C | 14.1°C | 9.7°C | 23.6°C | 6.0°C | 27 mm | 78% | 3.2 m/s | 4.9 |
| 2023 🔥 | 18.9°C | 14.9°C | 11.0°C | 27.0°C | 4.1°C | 71 mm | 79% | 3.5 m/s | 4.6 |
| 2022 | 17.7°C | 13.7°C | 9.6°C | 23.4°C | 6.0°C | 56 mm | 79% | 3.2 m/s | 4.5 |
| 2021 | 18.0°C | 13.5°C | 9.0°C | 24.1°C | 6.2°C | 62 mm | 78% | 3.4 m/s | 4.7 |
| 2020 | 17.9°C | 14.2°C | 10.5°C | 22.9°C | 6.4°C | 79 mm | 78% | 3.9 m/s | 4.3 |
| 2019 | 19.2°C | 14.6°C | 10.0°C | 25.2°C | 3.9°C | 26 mm | 78% | 3.1 m/s | 4.7 |
| 2018 | 17.4°C | 13.2°C | 9.0°C | 23.9°C | 3.4°C | 33 mm | 79% | 3.3 m/s | 4.4 |
| 2017 | 17.7°C | 13.7°C | 9.7°C | 22.8°C | 4.7°C | 71 mm | 78% | 3.3 m/s | 4.3 |
| 2016 ❄️ | 15.6°C | 11.5°C | 7.4°C | 18.4°C | 3.4°C | 75 mm | 79% | 3.4 m/s | 4.3 |
| 2015 | 18.5°C | 13.6°C | 8.7°C | 23.6°C | 4.6°C | 40 mm | 76% | 3.2 m/s | 4.7 |
| 2014 | 18.5°C | 14.6°C | 10.6°C | 24.7°C | 6.1°C | 95 mm | 82% | 3.5 m/s | 4.3 |
| 2013 🌧️ | 16.9°C | 14.0°C | 11.2°C | 20.0°C | 7.6°C | 194 mm | 82% | 4.5 m/s | 3.9 |
| 2012 | 17.6°C | 13.4°C | 9.1°C | 22.8°C | 4.9°C | 129 mm | 79% | 3.7 m/s | 4.4 |
| 2011 | 17.4°C | 13.5°C | 9.6°C | 20.0°C | 6.8°C | 110 mm | 80% | 3.5 m/s | 4.4 |
| 2010 | 18.6°C | 13.5°C | 8.4°C | 24.9°C | 5.8°C | 34 mm | 74% | 3.2 m/s | 4.7 |
| 2009 | 15.3°C | 12.1°C | 9.0°C | 18.6°C | 4.6°C | 158 mm | 80% | 4.3 m/s | 4 |
| 2008 | 17.0°C | 13.2°C | 9.3°C | 20.4°C | 4.7°C | 77 mm | 81% | 3.6 m/s | 4.4 |
| 2007 | 16.7°C | 13.6°C | 10.4°C | 20.9°C | 7.4°C | 135 mm | 83% | 3.7 m/s | 3.9 |
| 2006 | 17.5°C | 13.8°C | 10.1°C | 22.7°C | 4.9°C | 53 mm | 78% | 3.6 m/s | 4.2 |
| 2005 | 16.0°C | 12.5°C | 9.0°C | 18.2°C | 3.2°C | 122 mm | 81% | 4 m/s | 4.2 |
| 2004 | 16.7°C | 12.3°C | 8.0°C | 20.0°C | 3.9°C | 42 mm | 81% | 3 m/s | 4.5 |
| 2003 | 16.4°C | 12.9°C | 9.4°C | 21.7°C | 6.4°C | 117 mm | 81% | 4 m/s | 4.1 |
| 2002 | 16.6°C | 13.0°C | 9.4°C | 21.4°C | 5.8°C | 69 mm | 81% | 3.5 m/s | 4.5 |
| 2001 | 16.9°C | 13.3°C | 9.8°C | 23.5°C | 5.8°C | 113 mm | 80% | 3.6 m/s | 3.9 |
| 2000 | 17.7°C | 13.9°C | 10.1°C | 20.9°C | 6.9°C | 59 mm | 82% | 3.2 m/s | 4.2 |
| 1999 | 16.8°C | 12.9°C | 9.0°C | 22.2°C | 4.0°C | 120 mm | 82% | 3.5 m/s | 4.1 |
| 1998 | 16.5°C | 12.9°C | 9.2°C | 20.6°C | 3.9°C | 121 mm | 80% | 3.8 m/s | 4.4 |
| 1997 | 17.3°C | 13.4°C | 9.5°C | 20.8°C | 6.1°C | 98 mm | 84% | 3.2 m/s | 4.3 |
| 1996 | 16.3°C | 13.4°C | 10.4°C | 18.9°C | 6.8°C | 173 mm | 81% | 4.2 m/s | 4 |
| 1995 | 17.4°C | 13.6°C | 9.8°C | 20.2°C | 6.9°C | 75 mm | 83% | 3 m/s | 4.2 |
| 1994 | 17.9°C | 13.3°C | 8.8°C | 22.7°C | 4.9°C | 57 mm | 80% | 3.3 m/s | 4.7 |
| 1993 | 16.9°C | 12.9°C | 8.8°C | 21.9°C | 6.1°C | 112 mm | 82% | 3.4 m/s | 4.5 |
| 1992 | 15.2°C | 11.7°C | 8.2°C | 19.6°C | 5.3°C | 74 mm | 83% | 3.6 m/s | 4.5 |
| 1991 | 17.0°C | 13.4°C | 9.7°C | 20.5°C | 5.4°C | 85 mm | 82% | 3.2 m/s | 4.2 |
| 1990 | 17.6°C | 13.3°C | 9.0°C | 22.0°C | 5.4°C | 71 mm | 80% | 3 m/s | 4.3 |
| 1989 | 17.3°C | 13.7°C | 10.1°C | 20.8°C | 4.7°C | 79 mm | 79% | 3.7 m/s | 4.2 |
| 1988 | 17.4°C | 14.0°C | 10.5°C | 22.6°C | 6.7°C | 109 mm | 81% | 3.8 m/s | 4.3 |
| 1987 | 18.7°C | 13.9°C | 9.2°C | 24.6°C | 5.1°C | 40 mm | 79% | 3.1 m/s | 4.8 |
| 1986 | 17.5°C | 13.5°C | 9.4°C | 23.7°C | 6.8°C | 52 mm | 81% | 3.2 m/s | 4.2 |
| 1985 | 18.4°C | 13.6°C | 8.8°C | 23.0°C | 3.0°C | 47 mm | 77% | 3.2 m/s | 4.8 |
| 1984 | 17.0°C | 12.7°C | 8.5°C | 18.7°C | 4.8°C | 92 mm | 80% | 3.5 m/s | 4.8 |
| 1983 | 17.7°C | 14.3°C | 11.0°C | 21.7°C | 8.0°C | 117 mm | 82% | 3.5 m/s | — |
| 1982 | 17.8°C | 13.1°C | 8.5°C | 25.3°C | 3.4°C | 101 mm | 80% | 3 m/s | — |
| 1981 | 17.3°C | 13.3°C | 9.4°C | 21.7°C | 4.1°C | 99 mm | 82% | 3.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.4°C with lows near 9.5°C (mean 13.5°C), based on 45 years of NASA POWER data.
September averages 86 mm of rainfall in Bunbury, a relatively wet time of year. The wettest on record was 194 mm in 2013.
The hottest September reached 27°C in 2023. The coldest dipped to 3°C in 1985.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.6°C. Daytime highs moved from 17.6°C to 18.2°C and overnight lows from 9.2°C to 9.8°C over the same span.
September is one of the cooler months of the year in Bunbury and a relatively wet time of year, so plan for around 17.4°C daytime highs and 9.5°C at night.
Not quite — September is the 3rd coolest month in Bunbury, averaging 13.5°C.
For September in Bunbury, pack light layers you can adjust through the day, with typical highs of 17.4°C and lows of 9.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 80% — quite humid.
Average wind speed in September is 3.5 m/s. The windiest September on record averaged 4.5 m/s (2013).
The wettest September on record was 2013 with 194 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 Bunbury 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.
