September is one of the cooler months of the year in Geelong, with average highs near 15.8°C and lows around 7.2°C (mean 11.5°C). It is about average for rainfall, averaging 59 mm of rainfall and 77% relative humidity across the period.
September is one of the cooler months of the year in Geelong. Across 45 years of records, the warmest September in Geelong was 2023 — when the month averaged 14.2°C — while the coldest was 1992 at 9.3°C. Typical September days reach 15.8°C with nights near 7.2°C. The long-term trend is warming, about 0.4°C per decade.
September is about average for rainfall in Geelong, averaging 59 mm of rainfall. The wettest September on record was 1993 with 115 mm, while the driest was 2023 at 16 mm.
Relative humidity in Geelong during September averages 77%. The most humid September was 1992 at 84%, and the least humid was 2023 at 67%.
September receives about 4 kWh/m²/day of solar energy in Geelong. The sunniest September was 2023 at 4.5 kWh/m²/day, and the cloudiest were 1992, 2004 and 2009 at 3.6.
Average wind speed in Geelong during September is 4 m/s. The windiest September was 1996 at 5.1 m/s, while the calmest was 1997 at 2.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.0°C | 10.9°C | 11.7°C | 11.7°C | 12.4°C | +1.4°C |
| Avg High | 15.3°C | 15.0°C | 16.3°C | 16.1°C | 16.9°C | +1.6°C |
| Avg Low | 6.8°C | 6.8°C | 7.2°C | 7.4°C | 7.9°C | +1.1°C |
| Avg Rain | 62 mm | 74 mm | 60 mm | 50 mm | 45 mm | -17 mm |
September temperatures in Geelong have risen by about 1.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 2°C (2003) to a record high of 27.5°C (2023).
Rainfall in September is about average for rainfall, averaging 59 mm, with a wettest year of 115 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.5°C per decade while lows rose 0.3°C per decade, widening the gap between day and night.
A quieter season to visit Geelong
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Geelong. That said, September — with days averaging 15.8°C and nights around 7.2°C (mean 11.5°C) and moderate rainfall (59 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 | 16.9°C | 12.5°C | 8.0°C | 22.6°C | 3.1°C | 26 mm | 72% | 4.6 m/s | 4 |
| 2024 | 17.0°C | 12.6°C | 8.2°C | 23.1°C | 6.1°C | 42 mm | 71% | 4.7 m/s | 3.7 |
| 2023 🔥 | 19.7°C | 14.2°C | 8.7°C | 27.5°C | 4.5°C | 16 mm | 67% | 3.7 m/s | 4.5 |
| 2022 | 15.1°C | 11.4°C | 7.7°C | 18.3°C | 3.0°C | 53 mm | 81% | 3.6 m/s | 3.9 |
| 2021 | 16.4°C | 11.9°C | 7.5°C | 22.9°C | 4.4°C | 77 mm | 76% | 4.3 m/s | 4 |
| 2020 | 16.3°C | 11.9°C | 7.5°C | 22.0°C | 3.2°C | 57 mm | 76% | 4.2 m/s | 4.1 |
| 2019 | 16.6°C | 11.8°C | 7.1°C | 23.0°C | 4.7°C | 44 mm | 74% | 3.7 m/s | 4.1 |
| 2018 | 16.3°C | 11.3°C | 6.3°C | 23.0°C | 4.0°C | 18 mm | 71% | 3.8 m/s | 4.3 |
| 2017 | 16.3°C | 11.6°C | 7.0°C | 26.5°C | 3.3°C | 43 mm | 72% | 4.9 m/s | 3.8 |
| 2016 | 15.4°C | 11.4°C | 7.5°C | 20.6°C | 5.0°C | 73 mm | 81% | 3.6 m/s | 3.9 |
| 2015 | 16.5°C | 11.9°C | 7.4°C | 24.9°C | 4.6°C | 25 mm | 75% | 3.6 m/s | 4.1 |
| 2014 | 16.8°C | 12.3°C | 7.9°C | 25.9°C | 4.4°C | 37 mm | 77% | 3.6 m/s | 4.2 |
| 2013 | 16.9°C | 12.8°C | 8.8°C | 22.6°C | 2.6°C | 78 mm | 79% | 4.1 m/s | 3.9 |
| 2012 | 15.7°C | 11.6°C | 7.5°C | 22.5°C | 4.2°C | 54 mm | 78% | 4.1 m/s | 3.9 |
| 2011 | 16.7°C | 12.2°C | 7.6°C | 25.1°C | 4.6°C | 56 mm | 74% | 4.2 m/s | 4.2 |
| 2010 | 14.0°C | 10.4°C | 6.8°C | 18.1°C | 4.1°C | 71 mm | 83% | 3.9 m/s | 3.7 |
| 2009 | 16.3°C | 11.8°C | 7.3°C | 24.2°C | 4.9°C | 88 mm | 75% | 4.5 m/s | 3.6 |
| 2008 | 16.7°C | 11.8°C | 6.9°C | 25.2°C | 3.8°C | 35 mm | 72% | 4.1 m/s | 4.2 |
| 2007 | 16.4°C | 11.7°C | 7.0°C | 20.0°C | 3.9°C | 43 mm | 73% | 4.3 m/s | 4.1 |
| 2006 | 17.5°C | 12.5°C | 7.6°C | 25.9°C | 3.9°C | 44 mm | 70% | 3.9 m/s | 4.2 |
| 2005 | 16.3°C | 12.1°C | 7.8°C | 22.6°C | 3.2°C | 60 mm | 77% | 3.7 m/s | 4 |
| 2004 | 15.3°C | 11.3°C | 7.4°C | 21.9°C | 4.4°C | 66 mm | 82% | 3.4 m/s | 3.6 |
| 2003 | 14.7°C | 10.3°C | 5.9°C | 21.3°C | 2.0°C | 58 mm | 78% | 4.9 m/s | 4 |
| 2002 | 16.5°C | 11.8°C | 7.1°C | 24.5°C | 4.3°C | 56 mm | 70% | 4.9 m/s | 4 |
| 2001 | 17.0°C | 12.5°C | 7.9°C | 25.1°C | 4.1°C | 50 mm | 78% | 3.6 m/s | 3.9 |
| 2000 | 15.8°C | 11.6°C | 7.4°C | 20.6°C | 4.9°C | 98 mm | 81% | 4.6 m/s | 3.8 |
| 1999 | 17.2°C | 12.7°C | 8.2°C | 23.8°C | 5.1°C | 38 mm | 76% | 3.6 m/s | 4.1 |
| 1998 | 16.8°C | 12.3°C | 7.8°C | 24.0°C | 4.8°C | 54 mm | 77% | 4.1 m/s | 3.9 |
| 1997 | 15.4°C | 11.3°C | 7.2°C | 18.7°C | 5.0°C | 70 mm | 80% | 2.9 m/s | 4.2 |
| 1996 | 14.1°C | 10.1°C | 6.1°C | 19.7°C | 2.5°C | 114 mm | 81% | 5.1 m/s | 3.8 |
| 1995 | 14.3°C | 10.1°C | 6.0°C | 19.2°C | 3.4°C | 45 mm | 82% | 3.5 m/s | 3.8 |
| 1994 | 14.1°C | 9.9°C | 5.8°C | 20.7°C | 3.2°C | 56 mm | 76% | 4.2 m/s | 3.9 |
| 1993 🌧️ | 15.1°C | 11.2°C | 7.4°C | 22.7°C | 3.7°C | 115 mm | 83% | 3.8 m/s | 4.1 |
| 1992 ❄️ | 12.8°C | 9.3°C | 5.9°C | 15.6°C | 2.7°C | 110 mm | 84% | 3.6 m/s | 3.6 |
| 1991 | 14.5°C | 10.4°C | 6.4°C | 19.1°C | 3.1°C | 87 mm | 82% | 4 m/s | 3.9 |
| 1990 | 15.4°C | 11.2°C | 7.1°C | 21.7°C | 3.0°C | 55 mm | 79% | 3.9 m/s | 4.1 |
| 1989 | 15.1°C | 10.9°C | 6.7°C | 21.5°C | 3.8°C | 58 mm | 82% | 3.8 m/s | 4.4 |
| 1988 | 16.4°C | 11.9°C | 7.4°C | 20.4°C | 4.4°C | 54 mm | 77% | 4.3 m/s | 3.9 |
| 1987 | 16.4°C | 11.9°C | 7.4°C | 25.7°C | 3.3°C | 48 mm | 78% | 4 m/s | 4.2 |
| 1986 | 14.7°C | 10.7°C | 6.8°C | 20.4°C | 3.6°C | 67 mm | 83% | 3.8 m/s | 4 |
| 1985 | 14.5°C | 10.6°C | 6.7°C | 21.1°C | 3.3°C | 40 mm | 81% | 3.5 m/s | 4.4 |
| 1984 | 13.7°C | 9.9°C | 6.2°C | 19.3°C | 3.6°C | 108 mm | 81% | 3.9 m/s | 3.9 |
| 1983 | 14.6°C | 10.6°C | 6.6°C | 21.0°C | 3.1°C | 100 mm | 83% | 4.4 m/s | — |
| 1982 | 16.1°C | 11.1°C | 6.1°C | 24.1°C | 3.3°C | 48 mm | 71% | 3.9 m/s | — |
| 1981 | 16.4°C | 11.8°C | 7.2°C | 24.2°C | 4.8°C | 34 mm | 81% | 4.1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 15.8°C with lows near 7.2°C (mean 11.5°C), based on 45 years of NASA POWER data.
September averages 59 mm of rainfall in Geelong, about average for rainfall. The wettest on record was 115 mm in 1993.
The hottest September reached 27.5°C in 2023. The coldest dipped to 2°C in 2003.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.7°C. Daytime highs moved from 15.1°C to 17°C and overnight lows from 6.6°C to 8°C over the same span.
September is one of the cooler months of the year in Geelong and about average for rainfall, so plan for around 15.8°C daytime highs and 7.2°C at night.
Not quite — September is the 4th coolest month in Geelong, averaging 11.5°C.
For September in Geelong, pack warm layers and a jacket for chilly mornings, with typical highs of 15.8°C and lows of 7.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 77% — quite humid.
Average wind speed in September is 4 m/s. The windiest September on record averaged 5.1 m/s (1996).
The wettest September on record was 1993 with 115 mm. On average, September sees 59 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 Geelong 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.
