Perth has a Mediterranean climate with hot, dry summers from December to February and mild, wet winters from June to August. The city receives 3,200 hours of sunshine per year, making it the sunniest capital city in Australia. Average annual rainfall is 730mm, most of which falls between May and September. Sea temperatures range from 17degC in September to 22degC in February. Humidity is generally low year-round, rarely exceeding 60% even in winter. For more detailed information, see our guides to best time to visit Perth, things to do in Perth, and Perth travel tips.
Perth Weather by Month: Full Breakdown
| Month | Avg High (degC) | Avg Low (degC) | Rainfall (mm) | Sea Temp (degC) | Sunshine (hrs/day) |
|---|---|---|---|---|---|
| January | 31 | 18 | 9 | 22 | 11 |
| February | 31 | 18 | 13 | 22 | 10 |
| March | 29 | 16 | 19 | 22 | 9 |
| April | 26 | 14 | 44 | 21 | 7 |
| May | 22 | 11 | 118 | 20 | 6 |
| June | 19 | 9 | 177 | 19 | 5 |
| July | 18 | 8 | 170 | 18 | 5 |
| August | 19 | 8 | 135 | 17 | 7 |
| September | 20 | 9 | 81 | 17 | 8 |
| October | 23 | 11 | 52 | 18 | 9 |
| November | 26 | 14 | 22 | 19 | 10 |
| December | 29 | 16 | 11 | 21 | 11 |
Perth Weather in Summer: December to February
Summer in Perth is hot and almost completely dry. January and February both average 31degC (88degF) for daytime highs, with overnight lows around 18degC (64degF). Heatwaves can push temperatures above 40degC (104degF) for 3 to 5 consecutive days, usually driven by easterly winds from the desert interior. Rainfall is negligible at 9 to 13mm per month. The Fremantle Doctor, a cooling sea breeze, arrives most afternoons between 12pm and 3pm, dropping temperatures by 4 to 6degC within an hour. Sea temperatures peak at 22degC (72degF) in January and February, comfortable for swimming. Sunshine averages 11 hours per day in January.
Perth Weather in Autumn: March to May
Autumn brings gradual cooling and the first significant rain since the previous winter. March still feels like summer with highs of 29degC and only 19mm of rain. April drops to 26degC with 44mm of rain over about 6 wet days. May marks the real transition, with highs of 22degC and 118mm of rain across 12 days. This is when the landscape turns green after the brown summer. Sea temperatures stay warm at 22degC in March and 20degC in May. The Fremantle Doctor becomes less reliable by April.
Perth Weather in Winter: June to August
Winters are mild by European standards but distinctly cool and wet. July is the coldest month with average highs of 18degC (64degF) and lows of 8degC (46degF). Frost is rare in the city center but occasional in the Perth Hills. June is the wettest month with 177mm of rain over about 14 days, and July adds 170mm. Rain usually comes in fronts lasting 2 to 3 days, with clear, crisp days in between. Sea temperatures drop to 17 to 18degC. Snow has never been recorded in Perth city.
Perth Weather in Spring: September to November
Spring is Perth’s showpiece season. September starts cool (20degC) with 81mm of rain, but by October rainfall halves to 52mm and temperatures climb to 23degC. November averages 26degC with just 22mm of rain over 4 days. Wildflowers blanket the region from September through October, peaking in Kings Park and the Perth Hills. The Fremantle Doctor returns reliably by late October. This is the best season for outdoor activities, with 8 to 10 hours of daily sunshine and low humidity.
