Climate averages 1991–2020

Perth weather
by month.

See how the year changes. January (tied with February) has the highest average daily maximum; December has the lowest average monthly rainfall.

Pleasant-weather months by our simple rule: March April May October November December

Long-term climate patterns, not a forecast for a particular trip.

Warmest month 31.2°C January, average high

Coolest month 9.5°C July, average low

Wettest month 102 mm July, monthly total

Driest month 9.3 mm December, monthly total

Across the year Perth averages a daytime high of 23.7°C and a nighttime low of 14.0°C, with about 543 mm of rain on roughly 70 days. January (tied with February) is the warmest month (average high 31.2°C) and July the coolest (16.7°C). July is the wettest month with 102 mm; December is the driest with 9.3 mm.

Months with pleasant weather by a simple rule (average high between 18°C and 29°C, average low of at least 5°C and at most 8 rain days): March, April, May, October, November and December. This looks at temperature and rain only, not humidity, wind, sea temperature or crowds.

The annual picture

A year in Perth

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages 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

1991–2020

Monthly climate averages for Perth, 1991–2020
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	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

Nearby cities

Distance from Perth

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 limits

What do the high and low temperatures mean?

We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.

How is a rain day counted?

A local calendar day (standard time, UTC+8, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.

Where do the numbers come from?

ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at -32.00°, 115.90° (6 km from the city centre), adjusted down by 0.1°C for the difference between the city's elevation (34 m) and the cell's (17 m). Rain comes from the 0.25° cell at -32.00°, 115.75°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.

Does this page show sunshine, humidity or sea temperature?

No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.