December is one of the warmer months of the year in Mount Gambier, with average highs near 20°C and lows around 12.6°C (mean 16.3°C). It is one of the drier months, averaging 43 mm of rainfall and 71% relative humidity across the period.
December is one of the warmer months of the year in Mount Gambier. Across 45 years of records, the warmest December in Mount Gambier was 2015 — when the month averaged 18.4°C — while the coldest was 2001 at 14°C. Typical December days reach 20°C with nights near 12.6°C. The long-term December temperature trend is broadly flat.
December is one of the drier months in Mount Gambier, averaging 43 mm of rainfall. The wettest December on record was 2010 with 114 mm, while the driest was 1982 at 9 mm.
Relative humidity in Mount Gambier during December averages 71%. The most humid December was 1992 at 79%, and the least humid was 2015 at 64%.
December receives about 7.1 kWh/m²/day of solar energy in Mount Gambier. The sunniest December was 2021 at 8.2 kWh/m²/day, and the cloudiest was 2001 at 5.9.
Average wind speed in Mount Gambier during December is 3.9 m/s. The windiest December was 2005 at 4.7 m/s, while the calmest was 1983 at 3.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 16.1°C | 16.0°C | 16.3°C | 16.8°C | 16.1°C | 0°C |
| Avg High | 20.0°C | 19.6°C | 20.0°C | 20.6°C | 19.5°C | -0.5°C |
| Avg Low | 12.4°C | 12.4°C | 12.6°C | 13.0°C | 12.6°C | +0.2°C |
| Avg Rain | 40 mm | 43 mm | 42 mm | 38 mm | 58 mm | +18 mm |
December temperatures in Mount Gambier have stayed relatively stable across the record.
December has ranged from a record low of 8°C (1986) to a record high of 37.1°C (2019).
Rainfall in December is one of the drier months, averaging 43 mm, with a wettest year of 114 mm.
One of the best times to visit Mount Gambier
December is one of the best times to visit Mount Gambier. Expect days averaging 20°C and nights around 12.6°C (mean 16.3°C) — warmer than Mount Gambier's yearly average — with moderate rainfall (43 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 | 19.7°C | 15.9°C | 12.1°C | 29.9°C | 10.3°C | 41 mm | 68% | 4.1 m/s | — |
| 2024 | 21.3°C | 17.6°C | 13.9°C | 30.2°C | 12.1°C | 51 mm | 71% | 3.7 m/s | 7.5 |
| 2023 | 18.8°C | 15.9°C | 13.0°C | 28.1°C | 10.7°C | 106 mm | 78% | 4.2 m/s | 6.4 |
| 2022 | 19.8°C | 16.0°C | 12.2°C | 32.1°C | 9.8°C | 46 mm | 73% | 3.7 m/s | 7.3 |
| 2021 | 19.5°C | 16.0°C | 12.5°C | 28.4°C | 10.7°C | 10 mm | 70% | 3.8 m/s | 8.2 |
| 2020 | 18.1°C | 15.1°C | 12.0°C | 28.4°C | 9.7°C | 92 mm | 73% | 4.1 m/s | 6.9 |
| 2019 | 21.2°C | 17.0°C | 12.7°C | 37.1°C | 10.6°C | 21 mm | 69% | 4 m/s | 7.6 |
| 2018 | 22.0°C | 17.7°C | 13.5°C | 31.0°C | 10.6°C | 42 mm | 71% | 3.8 m/s | 6.9 |
| 2017 | 20.9°C | 17.3°C | 13.8°C | 32.0°C | 11.0°C | 17 mm | 70% | 3.9 m/s | 7 |
| 2016 | 20.1°C | 16.2°C | 12.4°C | 30.1°C | 9.6°C | 37 mm | 71% | 3.6 m/s | 7.3 |
| 2015 🔥 | 23.4°C | 18.4°C | 13.4°C | 34.0°C | 10.5°C | 12 mm | 64% | 3.7 m/s | 7.9 |
| 2014 | 19.6°C | 16.3°C | 13.0°C | 26.8°C | 10.8°C | 33 mm | 73% | 3.9 m/s | 7.2 |
| 2013 | 18.9°C | 15.5°C | 12.0°C | 28.3°C | 10.0°C | 36 mm | 75% | 3.6 m/s | 7.3 |
| 2012 | 20.2°C | 16.5°C | 12.9°C | 32.9°C | 10.5°C | 34 mm | 69% | 3.7 m/s | 7.3 |
| 2011 | 20.3°C | 16.6°C | 13.0°C | 27.1°C | 10.5°C | 31 mm | 73% | 3.7 m/s | 7.7 |
| 2010 🌧️ | 19.7°C | 16.4°C | 13.0°C | 27.5°C | 9.8°C | 114 mm | 75% | 3.9 m/s | 7.1 |
| 2009 | 20.6°C | 16.8°C | 13.0°C | 33.1°C | 11.1°C | 38 mm | 70% | 3.6 m/s | 7.5 |
| 2008 | 18.3°C | 15.3°C | 12.2°C | 26.2°C | 9.2°C | 107 mm | 74% | 4.2 m/s | 6.6 |
| 2007 | 20.8°C | 16.8°C | 12.9°C | 33.1°C | 9.9°C | 30 mm | 72% | 3.6 m/s | 7.3 |
| 2006 | 20.5°C | 16.1°C | 11.7°C | 34.3°C | 9.2°C | 12 mm | 65% | 3.9 m/s | 7.7 |
| 2005 | 21.0°C | 17.1°C | 13.2°C | 30.3°C | 10.9°C | 39 mm | 68% | 4.7 m/s | 7 |
| 2004 | 20.8°C | 17.1°C | 13.3°C | 29.4°C | 11.2°C | 30 mm | 72% | 3.6 m/s | 7.2 |
| 2003 | 20.9°C | 16.9°C | 12.8°C | 31.1°C | 9.6°C | 38 mm | 71% | 3.8 m/s | 7.3 |
| 2002 | 19.9°C | 16.2°C | 12.5°C | 30.6°C | 8.8°C | 39 mm | 70% | 4.3 m/s | 6.9 |
| 2001 ❄️ | 16.7°C | 14.0°C | 11.3°C | 23.6°C | 9.2°C | 68 mm | 77% | 4 m/s | 5.9 |
| 2000 | 20.0°C | 16.4°C | 12.8°C | 28.8°C | 10.3°C | 15 mm | 70% | 3.8 m/s | 7.9 |
| 1999 | 19.9°C | 16.5°C | 13.0°C | 29.5°C | 10.5°C | 60 mm | 72% | 4.4 m/s | 6.7 |
| 1998 | 20.7°C | 16.9°C | 13.0°C | 32.7°C | 10.2°C | 29 mm | 70% | 4 m/s | 7 |
| 1997 | 19.3°C | 16.0°C | 12.6°C | 25.2°C | 11.0°C | 19 mm | 74% | 4.1 m/s | 7.2 |
| 1996 | 18.5°C | 14.8°C | 11.1°C | 27.1°C | 9.3°C | 18 mm | 69% | 3.6 m/s | 7.2 |
| 1995 | 17.6°C | 14.5°C | 11.3°C | 24.2°C | 9.3°C | 46 mm | 72% | 4.4 m/s | 7.1 |
| 1994 | 21.6°C | 17.2°C | 12.9°C | 31.5°C | 8.3°C | 53 mm | 67% | 3.5 m/s | 7.7 |
| 1993 | 19.2°C | 15.6°C | 12.0°C | 30.6°C | 9.4°C | 81 mm | 72% | 4 m/s | 7 |
| 1992 | 20.0°C | 16.5°C | 13.1°C | 26.6°C | 10.2°C | 60 mm | 79% | 4 m/s | 6.1 |
| 1991 | 18.9°C | 15.4°C | 11.9°C | 29.2°C | 9.1°C | 23 mm | 75% | 3.9 m/s | 7.2 |
| 1990 | 20.0°C | 16.5°C | 13.0°C | 27.8°C | 10.3°C | 38 mm | 73% | 4 m/s | 6.8 |
| 1989 | 20.6°C | 16.6°C | 12.7°C | 29.9°C | 9.9°C | 23 mm | 69% | 3.9 m/s | 7.6 |
| 1988 | 20.4°C | 16.6°C | 12.8°C | 30.1°C | 10.6°C | 26 mm | 71% | 3.6 m/s | 7 |
| 1987 | 20.3°C | 16.0°C | 11.7°C | 30.6°C | 9.0°C | 46 mm | 68% | 3.8 m/s | 7.1 |
| 1986 | 18.3°C | 14.9°C | 11.5°C | 29.4°C | 8.0°C | 102 mm | 73% | 4.1 m/s | 6.7 |
| 1985 | 19.4°C | 16.2°C | 13.0°C | 27.9°C | 11.2°C | 73 mm | 74% | 4.2 m/s | 6.3 |
| 1984 | 19.4°C | 15.8°C | 12.2°C | 28.7°C | 10.2°C | 30 mm | 72% | 4.6 m/s | 7 |
| 1983 | 20.6°C | 16.6°C | 12.7°C | 29.9°C | 10.1°C | 34 mm | 71% | 3.2 m/s | — |
| 1982 | 20.5°C | 16.3°C | 12.1°C | 28.8°C | 9.8°C | 9 mm | 67% | 3.9 m/s | — |
| 1981 | 20.1°C | 16.3°C | 12.5°C | 30.4°C | 10.7°C | 14 mm | 70% | 3.7 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 20°C with lows near 12.6°C (mean 16.3°C), based on 45 years of NASA POWER data.
December averages 43 mm of rainfall in Mount Gambier, one of the drier months. The wettest on record was 114 mm in 2010.
The hottest December reached 37.1°C in 2019. The coldest dipped to 8°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 0.1°C — but days and nights have moved in opposite directions. Overnight lows rose from 12.5°C to 12.7°C while daytime highs eased from 20°C to 19.8°C, narrowing the gap between day and night.
December is one of the warmer months of the year in Mount Gambier and one of the drier months, so plan for around 20°C daytime highs and 12.6°C at night.
Not quite — December is the 9th coolest month in Mount Gambier, averaging 16.3°C.
For December in Mount Gambier, pack light layers you can adjust through the day, with typical highs of 20°C and lows of 12.6°C.
Relative humidity in December averages 71% — moderately humid.
Average wind speed in December is 3.9 m/s. The windiest December on record averaged 4.7 m/s (2005).
The wettest December on record was 2010 with 114 mm. On average, December sees 43 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 Mount Gambier behaves each December, 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 December specifically, along with year-by-year records and how the month has changed over the decades.
