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Perth weather by month: averages, rainfall & climate trends

Perth is the sunniest of Australia's capitals, a Mediterranean city on the Indian Ocean where the afternoon sea breeze known as the Fremantle Doctor is a daily summer institution. Perth weather by month: average temperatures, rainfall, records and how the climate has changed since 1940.

Today vs average

−1.2°Chigh near average

20° / 15°Today
21° / 13°Average
see today in detail →

How it's changed

+0.5°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–4943days above 30°C a year now (2016–2025) · 41 in the 1940sdays above 30°C · 41 in the 1940s+0.5°C vs the 1940s · see how it's changed →
Weather by montha typical year, averaged over the full recordJanuary, rain 12 mmhigh 29°low 19°February, rain 15 mmhigh 29°low 20°March, rain 16 mmhigh 27°low 18°April, rain 32 mmhigh 24°low 16°May, rain 82 mmhigh 20°low 14°June, rain 131 mmhigh 18°low 12°July, rain 128 mmhigh 17°low 11°August, rain 97 mmhigh 17°low 11°September, rain 55 mmhigh 18°low 12°October, rain 31 mmhigh 21°low 13°November, rain 19 mmhigh 24°low 16°December, rain 9 mmhigh 26°low 18°wettest month June, 131 mm · 626 mm a yearsee month by month →

Right now

What it's doing today vs the historical average for this date.
Partly cloudy

Right now

19.1°

16°feels like
46%humidity
7°dew point
18 km/hfrom SW
UV index4.8
sunrise05:33sunset18:30day length12h 56m
TodayPartly cloudy20°15°
MonMostly clear21°12°
TueMostly clear22°10°
WedPartly cloudy22°14°
ThuPartly cloudy19°14°
FriPartly cloudy18°12°
SatOvercast16°10°

On this date: October 18

Today (forecast)
20° / 15°
Average for October 18
21° / 13°

High near average · −1.2°C

  • Record high: 28.8° · 2010
  • Record low: 8.7° · 1947
  • One year ago: 21° / 13°

Every October 18 in history, coldest to hottest

▲ Daily highs▼ Daily lows

Dots show daily highs (top) and lows (bottom) for each October 18 on record (n = 87). Outlined dots are today's forecast.

Area we sample

Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.

Location & data

Historical weather for Perth is sampled from the ECMWF ERA5 reanalysis at 31.95°S, 115.86°E, with daily records since 1940.

Coordinates
31.95°S, 115.86°E
Time zone
Australia/Perth
Period
1940–2026
Data source
ERA5 (ECMWF)

Last 30 days

22 of the last 31 days were warmer than the historical average for that date. Average difference: +1.0°C.

Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.

This date over the years

One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.

Weather by month

Average temperatures and rainfall for each month: a typical year, from the full record.

Climate overview

Perth sits on the Indian Ocean coast in the far southwest of Australia, cut off by desert from the rest of the continent. Its hot-summer Mediterranean climate (Köppen Csa) brings hot, dry, sun-drenched summers from December to March and mild, wet winters, with most of the rain falling between May and September. On hot summer afternoons a southwesterly sea breeze, fondly called the Fremantle Doctor, blows in off the ocean and cools the afternoon down, and the city is the sunniest of all the Australian capitals.

The big long-term story is drying. Since the mid-1970s southwest Western Australia has seen a marked drop in winter rainfall, even as summer downpours have grown more intense, a shift tied to the broader changing climate. Hot, dry summers also leave the region open to bushfire, and the occasional remnant of a tropical cyclone drifting down from the northwest can break the summer calm with a burst of heavy rain.

The warmest month is February, with typical afternoon highs of 29.0°C and nights around 19.7°C. In a typical recent year, around 45 days reach 30°C or more. The coolest month is July, when afternoons reach about 16.7°C and overnight lows sit around 11.0°C. Freezing temperatures almost never occur.

In total, Perth averages about 626 mm of precipitation a year; June is usually the wettest month (131 mm) and December the driest (9 mm).

The record here starts in 1940, and since then the annual mean in Perth has climbed 0.5°C from the first ten years to the last ten. You can follow the shift year by year in the charts below.

Sources:en.wikipedia.orgbritannica.combom.gov.au

Climate graph (climograph)

February is the warmest month, July the coolest: a yearly swing of 10°C. Wettest month: June (~131 mm). Whole year averages ~626 mm of rain.

Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).

Rainy days by month

About 62 rainy days a year: most in July (~12), fewest in January (~1).

Bars = average number of days with ≥ 2 mm per month. Hover for the monthly rainfall total.

Monthly wind

Average daily peak wind at 10 m, by month.

Monthly solar energy

Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.

Perth month by month: what to expect

Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Record high/low are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.

MonthAvg highAvg lowRainRainy daysDaylightRecord highRecord low
January28.6°19.4°12 mm113.9 h40.7° (1961)11.8° (1988)
February29.0°19.7°15 mm113.1 h41.2° (1991)11.8° (1981)
March27.2°18.4°16 mm212.2 h38.7° (2007)10.0° (2007)
April23.7°16.0°32 mm411.2 h34.3° (2020)8.2° (1954)
May20.4°13.5°82 mm810.4 h30.3° (2002)6.4° (1979)
June17.8°11.9°131 mm129.9 h24.7° (1984)5.3° (1981)
July16.7°11.0°128 mm1210.1 h23.3° (1994)5.2° (2016)
August17.1°11.0°97 mm1010.8 h27.2° (2023)4.8° (1986)
September18.4°11.9°55 mm711.8 h30.8° (2023)5.7° (2008)
October20.6°13.3°31 mm412.8 h34.4° (2009)6.9° (1980)
November23.6°15.6°19 mm213.7 h36.9° (2023)7.3° (1992)
December26.3°17.8°9 mm114.1 h39.6° (2021)10.1° (1973)

How it's changed

Year-by-year signals from 1940 to today.

Climate stripes

Annual mean shifted from 1940–1949 to 2016–2025 by +0.5°C.

Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer

Annual mean temperature

Long-term trend: +0.08°C per decade.

One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.

Seasonal warming

Sep–Nov is warming fastest: +0.11°C per decade.

Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.

Hot days vs frost days

Days ≥ 30°C per year: 41.2 early in the record → 43.4 recently. Frost days: 0 → 0.

Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.

Yearly hot & cold extremes

All-time high in 1991, all-time low in 1986: 41.2°C / 4.8°C.

One point per year: the single hottest and coldest day recorded that year.

Annual rainfall

~626 mm/year on average. Last decade: −4% vs that average. Long-term trend: −7 mm per decade.

One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).

Day-by-day grid

Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).

Frequently asked questions about Perth

Which is the warmest month in Perth?
On long-term average, the warmest month in Perth is February (mean daily temperature of about 24.1°C) and the coolest is July (about 13.7°C).
How does today's temperature in Perth compare to the historical average?
On October 18, 2026, Perth is forecast to reach a high of 19.7°C and a low of 14.7°C. The long-term average for this date (the full record since 1940) is a high of 20.9°C and a low of 13.4°C, so today's high is 1.2°C cooler than that average.
How much has Perth warmed since 1940?
Comparing the first decade of the record (1940–1949) with the most recent (2016–2025), the annual mean temperature in Perth is about 0.5°C warmer.
How much does it rain in Perth?
Perth receives about 626 mm of precipitation per year on long-term average, with June typically the wettest month.
What is the average temperature in Perth?
Over the full record (since 1940), the annual mean temperature in Perth is about 18.5°C. The warmest month is February and the coolest is July.
What are the average temperatures in Perth by month?
Average daily highs and lows for each month in Perth (°C, full record since 1940): January 29°/19°, February 29°/20°, March 27°/18°, April 24°/16°, May 20°/14°, June 18°/12°, July 17°/11°, August 17°/11°, September 18°/12°, October 21°/13°, November 24°/16°, December 26°/18°.
What is the weather like in Perth in summer?
Summer in Perth (December to February) is dry and warm. Expect 26–29°C by day and 18–20°C at night, with February the warmest month. Rain picks up through the season, 9 mm in December to 15 mm in February. It is the driest season of the year.
What is the weather like in Perth in winter?
June to August is winter in Perth, and it is wet and fairly mild. Daytime highs sit at 17–18°C and nights at 11–12°C; August is the coldest month. Rain is steady at around 119 mm a month, spread over roughly 11 days. It is the wettest season of the year.
What is the weather like in Perth in spring?
In spring, September through November, Perth is mild. September starts at 18°C by day and 12°C at night; by November it is 24°C and 16°C. Rain eases through the season: 7 rainy days and 55 mm in September, 2 days and 19 mm in November.
What is the weather like in Perth in autumn?
Autumn in Perth (March to May) is pleasantly warm. It cools from 27°C by day and 18°C at night in March to 20°C and 14°C in May. Rain rises from 16 mm on 2 days in March to 82 mm on 8 days in May.
How many days a year does it rain in Perth?
On long-term average, Perth has about 62 days a year with at least 2 mm of rain or snow. The annual total is roughly 626 mm.

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