Weather in Perth

Rain is wet season runs from May to August, inside an annual total of 659 mm. The wettest month is July at 128 mm; the driest is December at 12 mm.

Perth is in Australia at 32.0°S. The 2001–2020 NASA POWER daily record describes a mild oceanic climate. February is the warmest month (average 23.6°C, high 27.0°C) and August is the coolest (average 15.6°C, low 13.5°C). On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are January, March, and December.

Best months to visit Perth

The three months with the highest comfort score are January, March, and December: January (23.0°C average, 18 mm, 65% humidity); March (22.7°C average, 20 mm, 65% humidity); December (21.4°C average, 12 mm, 65% humidity). Those months sit across the year end, so they are listed in season order rather than January-to-December. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the wet season itself — fewer crowds, greener landscape, heavier rain — aim at May–August instead of the score.

How warm Perth gets

The heat peaks in February, when the typical afternoon is 27.0°C. The opposite pole is August, when mornings average 13.5°C.

Mean high across all twelve months is 22.0°C and mean low is 16.4°C. These are 20-year grid averages, so a city station can read a few degrees warmer or cooler.

Rain through the year

The wet season in Perth starts in May and ends in August (May, June, July, and August). July is the core of it at 128 mm. December is the other extreme, with 12 mm.

A rainy day here is a day with at least 1 mm in the NASA POWER series. July averages 15 such days; December averages 3.

The calendar in Perth

Peak heat arrives in February: 27.0°C by day, 20.1°C at night, and 65% humidity. July is the wettest month — 128 mm and 15 rainy days, with 73% humidity.

By August the wet season is ending. Perth still sees about 106 mm, but the next month is usually leaner. December is the driest month, averaging only 12 mm across 3 rainy days. Highs sit near 24.7°C.

How Perth compares inside Australia

Adelaide is about 2131 km away: Perth is 0.7°C warmer than Adelaide in its hottest month and 229 mm wetter over the year than Adelaide. Adelaide’s wettest month is July (60 mm) versus July here.

Melbourne is about 2721 km away: Perth is 3.2°C warmer than Melbourne in its hottest month and 56 mm drier over the year than Melbourne. Melbourne’s wettest month is November (74 mm) versus July here.

Sydney is about 3290 km away: Perth is 0.4°C warmer than Sydney in its hottest month and 229 mm drier over the year than Sydney. Sydney’s wettest month is February (135 mm) versus July here.