Perth just had its third driest summer in 147 years of records, with the city only receiving 1.4 mm of rain during the last three months.

Summer is Perth’s driest time of year and in an average season, the city would only receive about 40 mm of rain. But even for its driest season, this summer has been exceptionally parched in Perth.

Image: Perth’s climatology showing Perth’s average monthly rainfall using green bars.

The official rain gauge in Perth only received 1.4 mm of rain between the start of December 2022 and the end of February 2023. This is the city’s third lowest summer total in records dating back to 1876, beaten only by 0.8 mm in 1974-75 and 0.2 mm in 2009-10.

Perth’s paltry rainfall this summer was recorded on only two days, with 1.0 mm in mid-December, 0.4 mm in early January, and nothing hitting the gauge in February.

While winter rainfall in Perth is frequent and heavy thanks to regular cold front activity, the city’s summer rainfall is more dependent on moisture being dragged down from the tropics. This can happen when tropical lows and cyclones drift south into the mid-latitudes, or when moisture is drawn down a West Coast Trough.

Unfortunately for Perth’s thirsty parks and gardens, all of the tropical cyclones that have developed to the northwest of Australia this season have not brought moisture down to southwestern Australia.

Image: The tracks of all tropical cyclones in the Australian region so far this season. Source: Meow via Wikimedia Commons

It has also been a hot summer in Perth, with the city’s final day of the season expected to reach around 37 to 38ºC on Tuesday.

This final burst of heat should see the city rounding out summer with an average maximum temperature of just under 31.4ºC. This would be the city’s 10th or equal 11th hottest summer in 126 years of records.