Climate averages 1991–2020
Perth weather
in December.
A hot, very dry month: the 3rd warmest and the driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
December is a hot month in Perth: daytime highs average 29.0°C and nights cool to about 17.1°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 9.3 mm of rain on roughly 2 days, which makes December a very dry month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 14 h 11 min on an average December day.
The nearest other city in this atlas is Mandurah (65 km away). In December its highs average 28.0°C, 1.0°C cooler than Perth, with 12 mm of rain.
Among the 32 cities listed in Australia, Perth ranks joint 5th of 32 for the warmest December highs and 1st of 32 for the driest December (rainfall, lowest first). The mean December high of those 32 cities is 26.0°C; Perth is 3.1°C warmer than that mean.
From December to January, average highs rise by 2.2°C to 31.2°C, and monthly rainfall rises from 9.3 mm to 17 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
Perth climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 31.2°C18.8°C | 18.8°C | 17 | 1.8 | 14.014 h |
| February | 31.2°C19.2°C | 19.2°C | 16 | 1.5 | 13.213 h |
| March | 28.9°C17.8°C | 17.8°C | 17 | 2.3 | 12.312 h |
| April | 24.8°C15.3°C | 15.3°C | 24 | 4.1 | 11.311 h |
| May | 20.9°C12.4°C | 12.4°C | 67 | 7.8 | 10.511 h |
| June | 17.9°C10.5°C | 10.5°C | 98 | 10.7 | 10.110 h |
| July | 16.7°C9.5°C | 9.5°C | 102 | 12.5 | 10.310 h |
| August | 17.2°C9.6°C | 9.6°C | 89 | 11.0 | 11.011 h |
| September | 18.5°C10.4°C | 10.4°C | 55 | 8.5 | 11.912 h |
| October | 22.0°C12.2°C | 12.2°C | 27 | 4.7 | 12.913 h |
| November | 25.7°C14.9°C | 14.9°C | 19 | 3.7 | 13.714 h |
| December, selected | 29.0°C17.1°C | 17.1°C | 9.3 | 1.6 | 14.214 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
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 Perth) is explained once on the Perth year overview and on the Sources, method and limits page.