December is one of the warmer months of the year in Onslow, with average highs near 30.7°C and lows around 24.5°C (mean 27.6°C). It is one of the drier months, averaging 8 mm of rainfall and 64% relative humidity across the period.
December is one of the warmer months of the year in Onslow. Across 45 years of records, the warmest December in Onslow was 2024 — when the month averaged 30.4°C — while the coldest was 2001 at 25.9°C. Typical December days reach 30.7°C with nights near 24.5°C. The long-term trend is warming, about 0.3°C per decade.
December is one of the drier months in Onslow, averaging 8 mm of rainfall. The wettest December on record was 1995 with 111 mm, while the driest were 2022, 2023 and 2025, among others at 0 mm.
Relative humidity in Onslow during December averages 64%. The most humid December was 2010 at 71%, and the least humid was 1985 at 57%.
December receives about 8.1 kWh/m²/day of solar energy in Onslow. The sunniest Decembers were 1985, 1986 and 2001 at 8.6 kWh/m²/day, and the cloudiest was 2012 at 7.
Average wind speed in Onslow during December is 5.3 m/s. The windiest Decembers were 1985 and 1995 at 6 m/s, while the calmest was 2012 at 4.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 27.2°C | 27.5°C | 27.3°C | 27.9°C | 28.6°C | +1.4°C |
| Avg High | 30.4°C | 30.6°C | 30.4°C | 30.8°C | 31.6°C | +1.2°C |
| Avg Low | 23.9°C | 24.4°C | 24.1°C | 25.0°C | 25.5°C | +1.6°C |
| Avg Rain | 5 mm | 19 mm | 2 mm | 9 mm | 5 mm | 0 mm |
December temperatures in Onslow have risen by about 1°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 19.7°C (1990) to a record high of 38.9°C (1981).
Rainfall in December is one of the drier months, averaging 8 mm, with a wettest year of 111 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0.4°C per decade, narrowing the gap between day and night.
A good time to visit Onslow
December is a good time to visit Onslow, with days averaging 30.7°C and nights around 24.5°C (mean 27.6°C, warmer than Onslow's yearly average) and low rainfall. September and August are marginally more temperate, but December still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 32.1°C | 29.0°C | 25.8°C | 37.0°C | 23.6°C | 0 mm | 62% | 5.1 m/s | — |
| 2024 🔥 | 33.3°C | 30.4°C | 27.5°C | 37.7°C | 22.6°C | 14 mm | 64% | 4.8 m/s | 7.7 |
| 2023 | 29.8°C | 26.9°C | 24.1°C | 33.7°C | 22.7°C | 0 mm | 68% | 5.7 m/s | 8.2 |
| 2022 | 30.2°C | 27.4°C | 24.5°C | 35.7°C | 22.2°C | 0 mm | 68% | 5.5 m/s | 8.1 |
| 2021 | 32.3°C | 28.7°C | 25.0°C | 36.7°C | 22.2°C | 0 mm | 59% | 5.7 m/s | 8.2 |
| 2020 | 31.8°C | 28.9°C | 25.9°C | 34.4°C | 23.8°C | 16 mm | 65% | 4.7 m/s | 7.7 |
| 2019 | 33.3°C | 30.0°C | 26.7°C | 37.4°C | 23.8°C | 0 mm | 59% | 4.6 m/s | 8.1 |
| 2018 | 30.1°C | 26.8°C | 23.4°C | 37.8°C | 20.5°C | 0 mm | 64% | 5.6 m/s | 8.3 |
| 2017 | 30.3°C | 27.6°C | 24.9°C | 34.1°C | 22.0°C | 4 mm | 67% | 5 m/s | 7.7 |
| 2016 | 31.7°C | 28.5°C | 25.3°C | 35.2°C | 22.2°C | 12 mm | 62% | 5.3 m/s | 7.7 |
| 2015 | 29.9°C | 26.7°C | 23.5°C | 36.1°C | 20.4°C | 0 mm | 65% | 5.9 m/s | 8.1 |
| 2014 | 30.8°C | 27.5°C | 24.2°C | 34.5°C | 21.2°C | 0 mm | 62% | 5.2 m/s | 8.3 |
| 2013 | 30.7°C | 28.0°C | 25.3°C | 35.8°C | 21.2°C | 14 mm | 66% | 4.8 m/s | 7.8 |
| 2012 | 31.1°C | 28.6°C | 26.2°C | 34.6°C | 21.9°C | 17 mm | 66% | 4.2 m/s | 7 |
| 2011 | 30.3°C | 27.6°C | 24.8°C | 37.9°C | 22.6°C | 0 mm | 66% | 5.4 m/s | 8.3 |
| 2010 | 30.1°C | 28.0°C | 25.8°C | 33.4°C | 22.9°C | 45 mm | 71% | 5.1 m/s | 7.6 |
| 2009 | 31.1°C | 27.9°C | 24.7°C | 35.0°C | 22.0°C | 0 mm | 63% | 5.5 m/s | 8.1 |
| 2008 | 29.7°C | 26.6°C | 23.4°C | 34.3°C | 19.9°C | 12 mm | 64% | 5.3 m/s | 8 |
| 2007 | 29.5°C | 26.7°C | 23.8°C | 34.0°C | 21.7°C | 3 mm | 66% | 5.1 m/s | 8.1 |
| 2006 | 31.1°C | 28.0°C | 24.8°C | 34.3°C | 21.9°C | 1 mm | 63% | 4.7 m/s | 8.3 |
| 2005 | 30.9°C | 27.5°C | 24.0°C | 35.4°C | 21.3°C | 1 mm | 58% | 5 m/s | 8 |
| 2004 | 31.3°C | 27.9°C | 24.6°C | 34.7°C | 21.4°C | 0 mm | 60% | 5.2 m/s | 8 |
| 2003 | 29.7°C | 26.4°C | 23.0°C | 36.0°C | 20.9°C | 0 mm | 67% | 5.6 m/s | 8.2 |
| 2002 | 30.9°C | 27.7°C | 24.5°C | 34.9°C | 21.7°C | 2 mm | 63% | 5 m/s | 8.5 |
| 2001 ❄️ | 28.8°C | 25.9°C | 22.9°C | 32.3°C | 20.7°C | 0 mm | 64% | 5.9 m/s | 8.6 |
| 2000 | 31.2°C | 28.4°C | 25.5°C | 38.2°C | 22.7°C | 3 mm | 66% | 4.8 m/s | 8 |
| 1999 | 30.7°C | 28.1°C | 25.4°C | 33.3°C | 21.9°C | 6 mm | 65% | 4.8 m/s | 7.9 |
| 1998 | 30.8°C | 28.0°C | 25.3°C | 34.4°C | 21.6°C | 43 mm | 68% | 5 m/s | 7.5 |
| 1997 | 31.6°C | 28.4°C | 25.2°C | 34.7°C | 22.9°C | 2 mm | 64% | 5.1 m/s | 8.2 |
| 1996 | 31.5°C | 28.3°C | 25.0°C | 36.3°C | 21.6°C | 11 mm | 62% | 5.1 m/s | 7.8 |
| 1995 🌧️ | 29.0°C | 26.4°C | 23.7°C | 34.1°C | 20.7°C | 111 mm | 69% | 6 m/s | 7.5 |
| 1994 | 31.8°C | 28.7°C | 25.6°C | 36.1°C | 23.9°C | 12 mm | 63% | 4.9 m/s | 8.1 |
| 1993 | 30.4°C | 27.2°C | 24.0°C | 33.5°C | 21.7°C | 3 mm | 64% | 5.8 m/s | 8.4 |
| 1992 | 29.5°C | 26.3°C | 23.0°C | 33.0°C | 20.5°C | 0 mm | 64% | 5.6 m/s | 8.5 |
| 1991 | 29.8°C | 26.4°C | 23.1°C | 34.3°C | 20.7°C | 0 mm | 62% | 5.7 m/s | 8.1 |
| 1990 | 31.1°C | 27.5°C | 24.0°C | 35.6°C | 19.7°C | 0 mm | 62% | 5.6 m/s | 8.5 |
| 1989 | 29.4°C | 26.2°C | 23.1°C | 34.1°C | 21.3°C | 0 mm | 64% | 5.9 m/s | 8.5 |
| 1988 | 30.3°C | 27.5°C | 24.7°C | 34.1°C | 21.6°C | 36 mm | 64% | 5.3 m/s | 7.9 |
| 1987 | 29.6°C | 26.3°C | 23.0°C | 35.6°C | 20.9°C | 0 mm | 63% | 5.7 m/s | 8.2 |
| 1986 | 30.9°C | 27.1°C | 23.3°C | 35.6°C | 20.5°C | 0 mm | 60% | 5.8 m/s | 8.6 |
| 1985 | 31.0°C | 27.1°C | 23.2°C | 36.3°C | 20.8°C | 0 mm | 57% | 6 m/s | 8.6 |
| 1984 | 30.0°C | 26.8°C | 23.5°C | 34.9°C | 21.2°C | 5 mm | 63% | 5.7 m/s | 7.8 |
| 1983 | 30.7°C | 27.8°C | 25.0°C | 34.3°C | 21.6°C | 1 mm | 63% | 5.4 m/s | — |
| 1982 | 31.4°C | 28.3°C | 25.2°C | 35.0°C | 22.5°C | 1 mm | 60% | 5.2 m/s | — |
| 1981 | 30.7°C | 27.4°C | 24.2°C | 38.9°C | 20.9°C | 3 mm | 64% | 5.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 30.7°C with lows near 24.5°C (mean 27.6°C), based on 45 years of NASA POWER data.
December averages 8 mm of rainfall in Onslow, one of the drier months. The wettest on record was 111 mm in 1995.
The hottest December reached 38.9°C in 1981. The coldest dipped to 19.7°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1°C. Daytime highs moved from 30.8°C to 31.5°C and overnight lows from 24.2°C to 25.4°C over the same span.
December is one of the warmer months of the year in Onslow and one of the drier months, so plan for around 30.7°C daytime highs and 24.5°C at night.
Not quite — December is the 8th coolest month in Onslow, averaging 27.6°C.
For December in Onslow, pack light, breathable clothing and sun protection, with typical highs of 30.7°C and lows of 24.5°C.
Relative humidity in December averages 64% — moderately humid.
Average wind speed in December is 5.3 m/s. The windiest December on record averaged 6 m/s (1985).
The wettest December on record was 1995 with 111 mm. On average, December sees 8 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 Onslow 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.
