December is one of the warmer months of the year in Mount Barker, with average highs near 26.9°C and lows around 13.6°C (mean 20.3°C). It is one of the drier months, averaging 24 mm of rainfall and 54% 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 2015 — when the month averaged 23.5°C — while the coldest was 2001 at 17.2°C. Typical December days reach 26.9°C with nights near 13.6°C. The long-term trend is warming, about 0.4°C per decade.
December is one of the drier months in Mount Barker, averaging 24 mm of rainfall. The wettest December on record was 1992 with 107 mm, while the driest were 2017 and 2018 at 0 mm.
Relative humidity in Mount Barker during December averages 54%. The most humid December was 1992 at 70%, and the least humid was 2015 at 43%.
December receives about 7.3 kWh/m²/day of solar energy in Mount Barker. The sunniest December was 2021 at 8.2 kWh/m²/day, and the cloudiest was 1992 at 6.
Average wind speed in Mount Barker during December is 3.2 m/s. The windiest December was 2002 at 3.6 m/s, while the calmest were 1983, 2009 and 2015 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 19.9°C | 19.6°C | 20.1°C | 21.3°C | 20.4°C | +0.5°C |
| Avg High | 26.6°C | 26.1°C | 26.6°C | 28.1°C | 27.0°C | +0.4°C |
| Avg Low | 13.1°C | 13.1°C | 13.5°C | 14.5°C | 13.7°C | +0.6°C |
| Avg Rain | 22 mm | 32 mm | 25 mm | 19 mm | 15 mm | -7 mm |
December temperatures in Mount Barker have risen by about 0.6°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 7.1°C (1994) to a record high of 44.5°C (2019).
Rainfall in December is one of the drier months, averaging 24 mm, with a wettest year of 107 mm.
One of the best times to visit Mount Barker
December is one of the best times to visit Mount Barker. Expect days averaging 26.9°C and nights around 13.6°C (mean 20.3°C) — warmer than Mount Barker's yearly average — with low rainfall (24 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 | 27.9°C | 20.8°C | 13.8°C | 39.2°C | 9.3°C | 19 mm | 47% | 3.2 m/s | — |
| 2024 | 28.3°C | 21.6°C | 14.9°C | 36.8°C | 10.9°C | 9 mm | 53% | 3 m/s | 7.9 |
| 2023 | 26.4°C | 20.1°C | 13.8°C | 36.0°C | 10.1°C | 20 mm | 58% | 3.5 m/s | 6.2 |
| 2022 | 26.5°C | 19.9°C | 13.2°C | 39.3°C | 9.2°C | 30 mm | 55% | 3.1 m/s | 7.7 |
| 2021 | 27.3°C | 20.3°C | 13.3°C | 38.4°C | 9.4°C | 3 mm | 53% | 3.1 m/s | 8.2 |
| 2020 | 25.8°C | 19.4°C | 12.9°C | 34.4°C | 9.0°C | 9 mm | 53% | 3.5 m/s | 7.5 |
| 2019 | 30.8°C | 23.1°C | 15.3°C | 44.5°C | 9.4°C | 1 mm | 45% | 3.1 m/s | 8 |
| 2018 | 30.3°C | 23.0°C | 15.8°C | 40.9°C | 10.3°C | 0 mm | 49% | 3.4 m/s | 7.1 |
| 2017 | 27.5°C | 21.0°C | 14.4°C | 38.6°C | 11.2°C | 0 mm | 52% | 3.1 m/s | 7.1 |
| 2016 | 27.9°C | 21.0°C | 14.1°C | 39.0°C | 9.2°C | 0 mm | 52% | 3.2 m/s | 7.4 |
| 2015 🔥 | 31.0°C | 23.5°C | 16.1°C | 41.0°C | 8.9°C | 35 mm | 43% | 2.8 m/s | 7.9 |
| 2014 | 26.3°C | 20.1°C | 13.9°C | 35.2°C | 10.4°C | 13 mm | 57% | 3 m/s | 7.1 |
| 2013 | 27.6°C | 20.8°C | 13.9°C | 40.0°C | 9.6°C | 22 mm | 52% | 3 m/s | 7.3 |
| 2012 | 27.2°C | 20.6°C | 14.0°C | 38.1°C | 10.1°C | 11 mm | 51% | 3.1 m/s | 7.5 |
| 2011 | 27.2°C | 20.5°C | 13.7°C | 36.8°C | 9.2°C | 32 mm | 55% | 2.9 m/s | 7.3 |
| 2010 | 25.0°C | 19.3°C | 13.6°C | 36.0°C | 9.0°C | 80 mm | 62% | 3.1 m/s | 6.9 |
| 2009 | 27.5°C | 20.5°C | 13.5°C | 38.9°C | 9.4°C | 25 mm | 54% | 2.8 m/s | 7.6 |
| 2008 | 24.4°C | 18.8°C | 13.2°C | 32.6°C | 8.5°C | 42 mm | 61% | 3.2 m/s | 6.6 |
| 2007 | 27.5°C | 20.7°C | 13.9°C | 40.8°C | 8.7°C | 35 mm | 53% | 3 m/s | 7.2 |
| 2006 | 27.6°C | 20.4°C | 13.2°C | 40.1°C | 8.1°C | 20 mm | 46% | 3.4 m/s | 7.6 |
| 2005 | 26.1°C | 19.9°C | 13.7°C | 39.7°C | 11.2°C | 36 mm | 57% | 3.5 m/s | 7.2 |
| 2004 | 26.4°C | 20.0°C | 13.7°C | 36.9°C | 9.3°C | 34 mm | 58% | 3.1 m/s | 7.4 |
| 2003 | 28.3°C | 21.4°C | 14.4°C | 38.5°C | 9.3°C | 22 mm | 55% | 3.2 m/s | 7.5 |
| 2002 | 27.4°C | 20.4°C | 13.4°C | 39.5°C | 8.3°C | 12 mm | 52% | 3.6 m/s | 7.3 |
| 2001 ❄️ | 22.8°C | 17.2°C | 11.7°C | 32.2°C | 8.5°C | 22 mm | 63% | 3.2 m/s | 7 |
| 2000 | 28.3°C | 21.2°C | 14.2°C | 39.7°C | 9.7°C | 7 mm | 50% | 3.1 m/s | 7.8 |
| 1999 | 25.9°C | 19.6°C | 13.2°C | 36.0°C | 9.9°C | 32 mm | 57% | 3.4 m/s | 7 |
| 1998 | 27.7°C | 20.8°C | 13.9°C | 40.3°C | 10.9°C | 9 mm | 54% | 3 m/s | 7 |
| 1997 | 26.7°C | 20.0°C | 13.4°C | 34.0°C | 10.2°C | 25 mm | 59% | 3 m/s | 7.4 |
| 1996 | 25.7°C | 19.0°C | 12.3°C | 36.6°C | 9.3°C | 16 mm | 54% | 3.2 m/s | 7.6 |
| 1995 | 25.2°C | 18.6°C | 11.9°C | 35.4°C | 7.3°C | 23 mm | 56% | 3.3 m/s | 7.2 |
| 1994 | 29.0°C | 21.5°C | 13.9°C | 39.1°C | 7.1°C | 10 mm | 47% | 2.9 m/s | 7.9 |
| 1993 | 24.8°C | 18.6°C | 12.5°C | 36.2°C | 7.7°C | 50 mm | 59% | 3.3 m/s | 7.2 |
| 1992 🌧️ | 24.6°C | 19.1°C | 13.7°C | 32.5°C | 10.1°C | 107 mm | 70% | 2.9 m/s | 6 |
| 1991 | 25.4°C | 18.9°C | 12.5°C | 34.7°C | 8.4°C | 7 mm | 57% | 3.2 m/s | 7.3 |
| 1990 | 26.1°C | 19.8°C | 13.5°C | 36.5°C | 9.1°C | 42 mm | 58% | 3.1 m/s | 6.8 |
| 1989 | 27.8°C | 20.8°C | 13.8°C | 37.5°C | 8.2°C | 10 mm | 52% | 3.1 m/s | 7.5 |
| 1988 | 26.9°C | 20.3°C | 13.8°C | 37.6°C | 9.1°C | 31 mm | 58% | 3.1 m/s | 7.2 |
| 1987 | 26.9°C | 19.8°C | 12.7°C | 36.9°C | 7.8°C | 37 mm | 54% | 3.2 m/s | 7.4 |
| 1986 | 24.5°C | 18.2°C | 11.9°C | 37.6°C | 7.7°C | 35 mm | 58% | 3.4 m/s | 6.7 |
| 1985 | 23.9°C | 18.1°C | 12.2°C | 35.6°C | 9.4°C | 35 mm | 59% | 3.5 m/s | 6.8 |
| 1984 | 26.7°C | 20.0°C | 13.4°C | 37.3°C | 9.7°C | 7 mm | 52% | 3.5 m/s | 7.1 |
| 1983 | 28.1°C | 21.0°C | 13.8°C | 38.5°C | 10.1°C | 28 mm | 53% | 2.8 m/s | — |
| 1982 | 28.1°C | 21.0°C | 14.0°C | 36.4°C | 8.9°C | 8 mm | 48% | 3.1 m/s | — |
| 1981 | 26.3°C | 19.5°C | 12.6°C | 39.2°C | 8.7°C | 9 mm | 54% | 3.1 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 26.9°C with lows near 13.6°C (mean 20.3°C), based on 45 years of NASA POWER data.
December averages 24 mm of rainfall in Mount Barker, one of the drier months. The wettest on record was 107 mm in 1992.
The hottest December reached 44.5°C in 2019. The coldest dipped to 7.1°C in 1994.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 0.6°C. Daytime highs moved from 26.6°C to 27.3°C and overnight lows from 13.2°C to 13.8°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 26.9°C daytime highs and 13.6°C at night.
Not quite — December is the 9th coolest month in Mount Barker, averaging 20.3°C.
For December in Mount Barker, pack light layers you can adjust through the day, with typical highs of 26.9°C and lows of 13.6°C.
Relative humidity in December averages 54% — relatively dry.
Average wind speed in December is 3.2 m/s. The windiest December on record averaged 3.6 m/s (2002).
The wettest December on record was 1992 with 107 mm. On average, December sees 24 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.
