Climate averages 1991–2020

Perth weather
in September.

A mild, moderately wet month: the 9th warmest and the 8th driest of the year.

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

Average high 18.5°C Daytime mean, September

Average low 10.4°C Night-time mean, September

Rainfall 55 mm 9 days with ≥1 mm

Daylight 12 h Sunrise to sunset, per day

September is a mild month in Perth: daytime highs average 18.5°C and nights cool to about 10.4°C. By daytime temperature it is the 9th warmest of the 12 months.

Expect about 55 mm of rain on roughly 9 days, which makes September a moderately wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 52 min on an average September day.

The nearest other city in this atlas is Mandurah (65 km away). In September its highs average 17.8°C, 0.7°C cooler than Perth, with 64 mm of rain.

Among the 32 cities listed in Australia, Perth ranks 19th of 32 for the warmest September highs and joint 24th of 32 for the driest September (rainfall, lowest first). The mean September high of those 32 cities is 20.0°C; Perth is 1.5°C cooler than that mean.

From September to October, average highs rise by 3.5°C to 22.0°C, and monthly rainfall falls from 55 mm to 27 mm.

The annual picture

September in context

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, selected	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

September in 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

How 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.