December is one of the warmer months of the year in Mount Barker, with average highs near 27.2°C and lows around 11.9°C (mean 19.6°C). It is one of the drier months, averaging 23 mm of rainfall and 61% relative humidity across the period.
December is one of the warmer months of the year in Mount Barker. Across 45 years of records, the warmest December in Mount Barker was 2019 — when the month averaged 23.2°C — while the coldest was 2001 at 16.2°C. Typical December days reach 27.2°C with nights near 11.9°C. The long-term trend is warming, about 0.3°C per decade.
December is one of the drier months in Mount Barker, averaging 23 mm of rainfall. The wettest December on record was 2001 with 82 mm, while the driest were 1994 and 2025 at 2 mm.
Relative humidity in Mount Barker during December averages 61%. The most humid December was 2008 at 72%, and the least humid was 2019 at 54%.
December receives about 7.5 kWh/m²/day of solar energy in Mount Barker. The sunniest December was 2019 at 8.4 kWh/m²/day, and the cloudiest was 1995 at 6.4.
Average wind speed in Mount Barker during December is 3.8 m/s. The windiest December was 1999 at 4.4 m/s, while the calmest was 2008 at 3.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.0°C | 19.6°C | 19.2°C | 20.0°C | 20.3°C | +1.3°C |
| Avg High | 26.8°C | 27.0°C | 26.8°C | 27.7°C | 28.0°C | +1.2°C |
| Avg Low | 11.3°C | 12.1°C | 11.7°C | 12.3°C | 12.5°C | +1.2°C |
| Avg Rain | 17 mm | 24 mm | 28 mm | 34 mm | 6 mm | -11 mm |
December temperatures in Mount Barker have risen by about 1.4°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 6°C (2007) to a record high of 43.2°C (1997).
Rainfall in December is one of the drier months, averaging 23 mm, with a wettest year of 82 mm.
One of the best times to visit Mount Barker
December is one of the best times to visit Mount Barker. Expect days averaging 27.2°C and nights around 11.9°C (mean 19.6°C) — warmer than Mount Barker's yearly average — with low rainfall (23 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 | 28.7°C | 20.9°C | 13.0°C | 39.7°C | 9.4°C | 2 mm | 58% | 3.8 m/s | — |
| 2024 | 28.7°C | 20.7°C | 12.7°C | 41.5°C | 7.8°C | 5 mm | 59% | 4.2 m/s | 7.7 |
| 2023 | 27.5°C | 20.4°C | 13.2°C | 37.8°C | 9.7°C | 3 mm | 58% | 4.3 m/s | 7.6 |
| 2022 | 26.7°C | 19.4°C | 12.1°C | 36.9°C | 8.5°C | 3 mm | 63% | 3.9 m/s | 7.3 |
| 2021 | 28.6°C | 20.3°C | 12.0°C | 40.2°C | 7.5°C | 8 mm | 59% | 3.9 m/s | 7.9 |
| 2020 | 28.0°C | 20.0°C | 12.0°C | 39.3°C | 8.1°C | 16 mm | 59% | 4.3 m/s | 7.8 |
| 2019 🔥 | 32.6°C | 23.2°C | 13.8°C | 41.1°C | 9.7°C | 7 mm | 54% | 3.6 m/s | 8.4 |
| 2018 | 28.0°C | 20.0°C | 11.9°C | 38.1°C | 7.9°C | 27 mm | 62% | 3.3 m/s | 7.7 |
| 2017 | 27.5°C | 19.9°C | 12.2°C | 38.8°C | 7.4°C | 40 mm | 61% | 3.4 m/s | 7.7 |
| 2016 | 26.5°C | 18.8°C | 11.1°C | 38.3°C | 7.7°C | 38 mm | 61% | 3.7 m/s | 7.7 |
| 2015 | 27.3°C | 19.6°C | 12.0°C | 39.4°C | 8.6°C | 37 mm | 60% | 3.8 m/s | 7.4 |
| 2014 | 25.8°C | 18.5°C | 11.3°C | 38.5°C | 7.0°C | 15 mm | 63% | 3.5 m/s | 7.4 |
| 2013 | 27.7°C | 19.8°C | 11.8°C | 39.2°C | 7.7°C | 27 mm | 61% | 3.5 m/s | 7.7 |
| 2012 | 29.5°C | 21.3°C | 13.0°C | 40.5°C | 8.6°C | 44 mm | 60% | 3.4 m/s | 7.3 |
| 2011 | 26.6°C | 19.8°C | 12.9°C | 38.0°C | 9.2°C | 74 mm | 68% | 3.8 m/s | 6.9 |
| 2010 | 25.5°C | 19.0°C | 12.5°C | 36.5°C | 9.3°C | 34 mm | 64% | 4.1 m/s | 6.7 |
| 2009 | 28.3°C | 20.0°C | 11.8°C | 38.8°C | 7.5°C | 7 mm | 58% | 3.5 m/s | 8 |
| 2008 | 24.3°C | 17.7°C | 11.0°C | 31.4°C | 8.6°C | 43 mm | 72% | 3.1 m/s | 7.5 |
| 2007 | 24.5°C | 17.9°C | 11.3°C | 41.4°C | 6.0°C | 63 mm | 64% | 3.8 m/s | 6.7 |
| 2006 | 29.5°C | 21.1°C | 12.6°C | 38.3°C | 7.6°C | 7 mm | 56% | 3.7 m/s | 7.9 |
| 2005 | 23.9°C | 17.1°C | 10.3°C | 32.0°C | 7.0°C | 25 mm | 66% | 4.3 m/s | 7.5 |
| 2004 | 29.7°C | 21.3°C | 12.8°C | 39.2°C | 8.9°C | 10 mm | 56% | 4 m/s | 8.1 |
| 2003 | 27.2°C | 19.4°C | 11.7°C | 40.8°C | 8.0°C | 13 mm | 63% | 3.8 m/s | 7.5 |
| 2002 | 28.7°C | 20.7°C | 12.8°C | 41.7°C | 7.6°C | 13 mm | 58% | 4.1 m/s | 7.1 |
| 2001 ❄️ 🌧️ | 22.2°C | 16.2°C | 10.1°C | 31.1°C | 7.9°C | 82 mm | 71% | 3.5 m/s | 6.7 |
| 2000 | 29.2°C | 20.8°C | 12.5°C | 39.8°C | 8.3°C | 13 mm | 59% | 3.8 m/s | 8.2 |
| 1999 | 27.2°C | 20.2°C | 13.2°C | 34.1°C | 8.5°C | 29 mm | 63% | 4.4 m/s | 7.3 |
| 1998 | 27.2°C | 19.9°C | 12.5°C | 36.3°C | 7.2°C | 29 mm | 64% | 3.7 m/s | 7.2 |
| 1997 | 28.4°C | 20.5°C | 12.5°C | 43.2°C | 9.0°C | 16 mm | 60% | 4 m/s | 7.9 |
| 1996 | 24.2°C | 17.6°C | 11.0°C | 35.0°C | 7.3°C | 31 mm | 64% | 3.6 m/s | 7.3 |
| 1995 | 24.8°C | 18.5°C | 12.2°C | 33.1°C | 9.1°C | 69 mm | 67% | 3.9 m/s | 6.4 |
| 1994 | 29.5°C | 21.0°C | 12.5°C | 38.3°C | 8.7°C | 2 mm | 56% | 3.7 m/s | 8.3 |
| 1993 | 27.9°C | 19.5°C | 11.1°C | 40.5°C | 6.4°C | 9 mm | 57% | 4 m/s | 8.1 |
| 1992 | 26.0°C | 18.5°C | 11.0°C | 34.7°C | 6.2°C | 22 mm | 64% | 3.4 m/s | 7.7 |
| 1991 | 28.5°C | 20.6°C | 12.6°C | 37.2°C | 7.1°C | 27 mm | 60% | 3.5 m/s | 7.4 |
| 1990 | 26.4°C | 19.3°C | 12.1°C | 34.4°C | 8.3°C | 9 mm | 62% | 3.5 m/s | 7.4 |
| 1989 | 27.4°C | 19.2°C | 11.1°C | 35.9°C | 7.2°C | 10 mm | 56% | 4 m/s | 7.9 |
| 1988 | 26.1°C | 18.8°C | 11.5°C | 33.9°C | 7.6°C | 15 mm | 63% | 3.7 m/s | 7.3 |
| 1987 | 28.1°C | 20.1°C | 12.1°C | 39.1°C | 8.9°C | 21 mm | 62% | 4.1 m/s | 7.3 |
| 1986 | 26.2°C | 18.3°C | 10.4°C | 34.5°C | 6.4°C | 4 mm | 59% | 3.6 m/s | 7.6 |
| 1985 | 25.1°C | 17.6°C | 10.2°C | 36.2°C | 6.6°C | 16 mm | 60% | 3.8 m/s | 7.3 |
| 1984 | 25.6°C | 18.0°C | 10.5°C | 32.9°C | 6.5°C | 16 mm | 60% | 3.7 m/s | 6.9 |
| 1983 | 28.2°C | 20.1°C | 12.0°C | 40.1°C | 6.4°C | 44 mm | 61% | 3.6 m/s | — |
| 1982 | 28.7°C | 20.8°C | 13.0°C | 38.0°C | 6.2°C | 13 mm | 59% | 3.8 m/s | — |
| 1981 | 25.7°C | 18.1°C | 10.5°C | 36.1°C | 6.5°C | 11 mm | 58% | 4 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 27.2°C with lows near 11.9°C (mean 19.6°C), based on 45 years of NASA POWER data.
December averages 23 mm of rainfall in Mount Barker, one of the drier months. The wettest on record was 82 mm in 2001.
The hottest December reached 43.2°C in 1997. The coldest dipped to 6°C in 2007.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.4°C. Daytime highs moved from 26.7°C to 28°C and overnight lows from 11.2°C to 12.6°C over the same span.
December is one of the warmer months of the year in Mount Barker and one of the drier months, so plan for around 27.2°C daytime highs and 11.9°C at night.
Not quite — December is the 9th coolest month in Mount Barker, averaging 19.6°C.
For December in Mount Barker, pack light layers you can adjust through the day, with typical highs of 27.2°C and lows of 11.9°C.
Relative humidity in December averages 61% — moderately humid.
Average wind speed in December is 3.8 m/s. The windiest December on record averaged 4.4 m/s (1999).
The wettest December on record was 2001 with 82 mm. On average, December sees 23 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 Barker 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.
