December is one of the warmer months of the year in Sydney, with average highs near 24.3°C and lows around 18.7°C (mean 21.5°C). It is about average for rainfall, averaging 75 mm of rainfall and 73% relative humidity across the period.
December is one of the warmer months of the year in Sydney. Across 45 years of records, the warmest December in Sydney was 1990 — when the month averaged 23.5°C — while the coldest was 2011 at 19.1°C. Typical December days reach 24.3°C with nights near 18.7°C. The long-term trend is warming, about 0.2°C per decade.
December is about average for rainfall in Sydney, averaging 75 mm of rainfall. The wettest December on record was 1991 with 199 mm, while the driest was 2019 at 2 mm.
Relative humidity in Sydney during December averages 73%. The most humid December was 1992 at 81%, and the least humid was 1984 at 66%.
December receives about 6.6 kWh/m²/day of solar energy in Sydney. The sunniest December was 2005 at 7.8 kWh/m²/day, and the cloudiest was 2020 at 5.7.
Average wind speed in Sydney during December is 3.1 m/s. The windiest December was 2002 at 3.6 m/s, while the calmest was 2005 at 2.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.1°C | 21.1°C | 21.7°C | 21.8°C | 21.8°C | +0.7°C |
| Avg High | 23.9°C | 23.9°C | 24.6°C | 24.6°C | 24.5°C | +0.6°C |
| Avg Low | 18.3°C | 18.3°C | 18.9°C | 18.9°C | 19.1°C | +0.8°C |
| Avg Rain | 81 mm | 82 mm | 64 mm | 74 mm | 73 mm | -8 mm |
December temperatures in Sydney have risen by about 0.5°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 13.6°C (1995) to a record high of 37.6°C (2019).
Rainfall in December is about average for rainfall, averaging 75 mm, with a wettest year of 199 mm.
One of the best times to visit Sydney
December is one of the best times to visit Sydney. Expect days averaging 24.3°C and nights around 18.7°C (mean 21.5°C) — warmer than Sydney's yearly average — with moderate rainfall (75 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 | 25.7°C | 22.3°C | 19.0°C | 37.3°C | 15.1°C | 51 mm | 67% | 3.1 m/s | — |
| 2024 | 25.8°C | 22.9°C | 20.0°C | 31.8°C | 17.5°C | 33 mm | 74% | 2.9 m/s | 7.3 |
| 2023 | 25.6°C | 22.8°C | 20.1°C | 35.9°C | 18.4°C | 124 mm | 78% | 3 m/s | 6.7 |
| 2022 | 22.5°C | 19.9°C | 17.3°C | 29.0°C | 14.2°C | 30 mm | 71% | 3.3 m/s | 7.1 |
| 2021 | 23.4°C | 21.2°C | 19.0°C | 30.0°C | 16.0°C | 90 mm | 78% | 3.2 m/s | 6.5 |
| 2020 | 23.8°C | 21.4°C | 18.9°C | 31.6°C | 16.4°C | 109 mm | 74% | 3.2 m/s | 5.7 |
| 2019 | 25.7°C | 22.2°C | 18.7°C | 37.6°C | 15.2°C | 2 mm | 68% | 3.1 m/s | 7 |
| 2018 | 24.9°C | 22.1°C | 19.3°C | 29.9°C | 16.3°C | 118 mm | 78% | 2.8 m/s | 7.1 |
| 2017 | 26.1°C | 23.0°C | 19.9°C | 34.3°C | 17.7°C | 57 mm | 76% | 3 m/s | 6.5 |
| 2016 | 26.0°C | 22.9°C | 19.8°C | 33.6°C | 17.4°C | 68 mm | 73% | 2.9 m/s | 6.7 |
| 2015 | 24.6°C | 21.8°C | 19.0°C | 31.0°C | 16.9°C | 72 mm | 71% | 3 m/s | 6.8 |
| 2014 | 24.2°C | 21.7°C | 19.2°C | 29.5°C | 17.1°C | 144 mm | 77% | 3 m/s | 6.5 |
| 2013 | 25.0°C | 21.9°C | 18.7°C | 34.5°C | 14.0°C | 43 mm | 70% | 3 m/s | 7.3 |
| 2012 | 24.4°C | 21.5°C | 18.5°C | 34.1°C | 15.8°C | 43 mm | 73% | 3.4 m/s | 6.1 |
| 2011 ❄️ | 20.9°C | 19.1°C | 17.3°C | 26.4°C | 14.2°C | 88 mm | 76% | 3.4 m/s | 5.9 |
| 2010 | 23.9°C | 21.3°C | 18.7°C | 29.3°C | 13.7°C | 107 mm | 77% | 2.8 m/s | 6.3 |
| 2009 | 24.7°C | 21.9°C | 19.2°C | 32.4°C | 16.5°C | 69 mm | 74% | 3.4 m/s | 6.3 |
| 2008 | 24.5°C | 21.2°C | 18.0°C | 32.0°C | 16.3°C | 83 mm | 72% | 3.1 m/s | 6.6 |
| 2007 | 23.3°C | 21.2°C | 19.1°C | 26.6°C | 17.3°C | 105 mm | 77% | 3.3 m/s | 6.1 |
| 2006 | 23.7°C | 21.0°C | 18.2°C | 31.4°C | 14.2°C | 69 mm | 72% | 3.4 m/s | 6.3 |
| 2005 | 26.0°C | 22.5°C | 18.9°C | 33.2°C | 15.0°C | 28 mm | 69% | 2.7 m/s | 7.8 |
| 2004 | 23.5°C | 20.9°C | 18.3°C | 33.3°C | 14.7°C | 86 mm | 74% | 3.4 m/s | 6.7 |
| 2003 | 24.7°C | 21.9°C | 19.2°C | 33.0°C | 16.9°C | 53 mm | 75% | 3.2 m/s | 6.2 |
| 2002 | 24.4°C | 21.6°C | 18.8°C | 35.3°C | 15.8°C | 64 mm | 70% | 3.6 m/s | 6.8 |
| 2001 | 25.1°C | 22.0°C | 18.9°C | 32.4°C | 16.6°C | 31 mm | 69% | 3.1 m/s | 6.5 |
| 2000 | 25.8°C | 23.0°C | 20.1°C | 33.9°C | 15.8°C | 46 mm | 70% | 2.9 m/s | 7.1 |
| 1999 | 23.0°C | 20.6°C | 18.2°C | 27.6°C | 15.8°C | 90 mm | 74% | 3.4 m/s | 6.3 |
| 1998 | 24.7°C | 22.2°C | 19.7°C | 29.7°C | 16.4°C | 41 mm | 74% | 3.2 m/s | 6.8 |
| 1997 | 26.4°C | 23.2°C | 20.0°C | 33.2°C | 17.6°C | 33 mm | 71% | 3.2 m/s | 6.5 |
| 1996 | 23.2°C | 20.2°C | 17.2°C | 29.9°C | 14.5°C | 57 mm | 73% | 3.3 m/s | 6.4 |
| 1995 | 22.1°C | 19.5°C | 16.8°C | 27.9°C | 13.6°C | 82 mm | 75% | 3.4 m/s | 6.4 |
| 1994 | 23.5°C | 20.9°C | 18.2°C | 35.8°C | 15.4°C | 59 mm | 75% | 3.3 m/s | 6.6 |
| 1993 | 24.1°C | 21.1°C | 18.1°C | 31.6°C | 15.2°C | 42 mm | 72% | 3.3 m/s | 6.6 |
| 1992 | 22.2°C | 20.1°C | 18.0°C | 27.6°C | 15.1°C | 174 mm | 81% | 3.1 m/s | 6.1 |
| 1991 🌧️ | 22.6°C | 20.0°C | 17.5°C | 27.5°C | 14.9°C | 199 mm | 75% | 3.1 m/s | 6.4 |
| 1990 🔥 | 27.2°C | 23.5°C | 19.7°C | 35.9°C | 14.8°C | 40 mm | 71% | 2.9 m/s | 7.3 |
| 1989 | 23.4°C | 20.6°C | 17.8°C | 30.7°C | 15.2°C | 111 mm | 73% | 3.1 m/s | 6.9 |
| 1988 | 23.4°C | 21.2°C | 18.9°C | 30.1°C | 16.2°C | 126 mm | 80% | 3.1 m/s | 6.1 |
| 1987 | 23.5°C | 20.9°C | 18.2°C | 32.9°C | 15.0°C | 86 mm | 72% | 3.2 m/s | 6.4 |
| 1986 | 23.1°C | 20.4°C | 17.6°C | 29.3°C | 13.9°C | 29 mm | 69% | 3.3 m/s | 7.5 |
| 1985 | 25.5°C | 22.3°C | 19.2°C | 31.8°C | 15.6°C | 87 mm | 70% | 2.8 m/s | 6.7 |
| 1984 | 23.9°C | 20.9°C | 17.9°C | 31.1°C | 14.8°C | 77 mm | 66% | 3.3 m/s | 7 |
| 1983 | 23.6°C | 20.7°C | 17.9°C | 34.3°C | 14.6°C | 97 mm | 72% | 3.1 m/s | — |
| 1982 | 24.3°C | 21.3°C | 18.4°C | 30.8°C | 15.6°C | 27 mm | 71% | 3 m/s | — |
| 1981 | 24.6°C | 21.5°C | 18.4°C | 32.4°C | 16.4°C | 92 mm | 73% | 2.9 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 24.3°C with lows near 18.7°C (mean 21.5°C), based on 45 years of NASA POWER data.
December averages 75 mm of rainfall in Sydney, about average for rainfall. The wettest on record was 199 mm in 1991.
The hottest December reached 37.6°C in 2019. The coldest dipped to 13.6°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 0.5°C. Daytime highs moved from 24.4°C to 24.6°C and overnight lows from 18.4°C to 19.1°C over the same span.
December is one of the warmer months of the year in Sydney and about average for rainfall, so plan for around 24.3°C daytime highs and 18.7°C at night.
Not quite — December is the 9th coolest month in Sydney, averaging 21.5°C.
For December in Sydney, pack light layers you can adjust through the day, with typical highs of 24.3°C and lows of 18.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 73% — moderately humid.
Average wind speed in December is 3.1 m/s. The windiest December on record averaged 3.6 m/s (2002).
The wettest December on record was 1991 with 199 mm. On average, December sees 75 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 Sydney 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.
