Climate averages 1991–2020
Blue Mountains weather
in December.
A warm, wet month: the 3rd warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a warm month in Blue Mountains: daytime highs average 22.1°C and nights cool to about 11.0°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 121 mm of rain on roughly 14 days, which makes December a wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 21 min on an average December day.
The nearest other city in this atlas is Sydney (83 km away). In December its highs average 24.2°C, 2.1°C warmer than Blue Mountains, with 60 mm of rain.
Among the 32 cities listed in Australia, Blue Mountains ranks joint 28th of 32 for the warmest December highs and 29th of 32 for the driest December (rainfall, lowest first). The mean December high of those 32 cities is 26.0°C; Blue Mountains is 3.9°C cooler than that mean.
From December to January, average highs rise by 1.6°C to 23.6°C, and monthly rainfall rises from 121 mm to 126 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Blue Mountains climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 23.6°C12.8°C | 12.8°C | 126 | 15.5 | 14.114 h |
| February | 22.2°C12.6°C | 12.6°C | 148 | 15.4 | 13.313 h |
| March | 19.9°C10.8°C | 10.8°C | 115 | 15.1 | 12.312 h |
| April | 16.8°C7.7°C | 7.7°C | 56 | 9.1 | 11.311 h |
| May | 13.3°C4.6°C | 4.6°C | 48 | 6.6 | 10.410 h |
| June | 10.4°C2.7°C | 2.7°C | 62 | 7.7 | 10.010 h |
| July | 9.9°C1.5°C | 1.5°C | 37 | 6.3 | 10.110 h |
| August | 11.5°C1.8°C | 1.8°C | 46 | 6.7 | 10.911 h |
| September | 15.0°C4.3°C | 4.3°C | 53 | 8.3 | 11.912 h |
| October | 18.0°C6.6°C | 6.6°C | 75 | 10.5 | 12.913 h |
| November | 20.1°C8.9°C | 8.9°C | 109 | 13.7 | 13.814 h |
| December, selected | 22.1°C11.0°C | 11.0°C | 121 | 13.5 | 14.314 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Sydney in DecemberAustralia · 83 kmHigh 24.2°C · Low 17.8°C · 60 mm rain
- Wollongong in DecemberAustralia · 95 kmHigh 23.5°C · Low 17.5°C · 72 mm rain
- Central Coast in DecemberAustralia · 101 kmHigh 24.4°C · Low 18.4°C · 70 mm rain
- Maitland in DecemberAustralia · 158 kmHigh 27.5°C · Low 17.6°C · 71 mm rain
- Newcastle, Australia in DecemberAustralia · 160 kmHigh 24.7°C · Low 18.6°C · 70 mm rain
- Canberra in DecemberAustralia · 206 kmHigh 24.3°C · Low 12.1°C · 55 mm rain
- Tuggeranong in DecemberAustralia · 222 kmHigh 24.3°C · Low 12.1°C · 81 mm rain
- Coffs Harbour in DecemberAustralia · 462 kmHigh 25.7°C · Low 19.5°C · 150 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Blue Mountains) is explained once on the Blue Mountains year overview and on the Sources, method and limits page.