Perth weather in September
In September, Perth has an average high of 18 °C64 °F and an average low of 13 °C56 °F, with about 70 mm2.7 in of precipitation. It is the 10th warmest month of the year and ranks 5th for precipitation.
How September compares with other months
Compared with August, September is about the same temperature and drier by 37 mm1.4 in. Compared with October, September is 1.4 °C2.6 °F cooler on average and wetter by 37 mm1.5 in. Daylight lasts about 11.9 hours around the middle of the month. Average relative humidity is 73% and the average cloud amount 53%.
Is September a good time to visit Perth?
September is not among the most comfortable months by our comfort score: it is cool (average high 18 °C64 °F) and it is fairly wet (70 mm2.7 in). The most comfortable months in Perth are October–May.
What to wear in September
For Perth in September, pack light layers — T-shirts plus a light sweater or jacket.
September in nearby places
| Place | High °C°F | Low °C°F | Precip. mmin |
|---|---|---|---|
| Perth | 1864 | 1356 | 702.7 |
| Mandurah | 1864 | 1356 | 833.3 |
| Augusta | 1661 | 1457 | 763.0 |
| Roebourne | 3493 | 1763 | 20.1 |
| Marble Bar | 3595 | 1762 | 30.1 |
Nearby places that are more than 1 °C1.8 °F warmer in September: Roebourne and Marble Bar.
Other months in Perth
- January26 °C79 °F / 19 °C66 °F
- February27 °C80 °F / 20 °C68 °F
- March26 °C78 °F / 19 °C66 °F
- April23 °C73 °F / 17 °C63 °F
- May21 °C69 °F / 16 °C60 °F
- June19 °C66 °F / 14 °C58 °F
- July18 °C64 °F / 14 °C56 °F
- August18 °C64 °F / 13 °C56 °F
- September18 °C64 °F / 13 °C56 °F
- October20 °C68 °F / 14 °C58 °F
- November22 °C72 °F / 16 °C61 °F
- December24 °C76 °F / 18 °C64 °F
Frequently asked questions
How warm is Perth in September?
In September the average high in Perth is 18 °C (64 °F) and the average low is 13 °C (56 °F).
Does it rain a lot in Perth in September?
On average about 70 mm (2.7 in) of precipitation falls in September; it ranks 5th of the 12 months.
Is September the warmest month in Perth?
No. The warmest month in Perth is February, with an average high of 27 °C (80 °F). The coldest month is September, with an average low of 13 °C (56 °F).
How long is the day in Perth in September?
In the middle of September the day in Perth lasts about 11.9 hours from sunrise to sunset. The value is calculated from the position of the city and the sun.
How humid is Perth in September?
The average relative humidity in September is about 73%. This is a long-term average for the whole day.
How cloudy is Perth in September?
On average about 53% of the sky is covered by cloud in September. This is the mean cloud amount from satellite data, not the number of sunny days.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.