Western Australia has had its hottest start to winter on record with Perth enduring its equal-hottest June ever, as a wet end to the month failed to prevent the city from finishing up with below-average rainfall.
Overall it was hotter than a typical September in Perth, with the mean maximum temperature coming in at 21.4 degrees Celsius — well above the June average of 19.5C.
"That equalled the record that was set in June 2017 and our temperature records for Perth metro go back to 1897," Bureau of Meteorology (BOM) spokesman Neil Bennett said.
"Overnight temperatures were also very warm, the average was 10.7C. That's 2.1C above the long term average of 8.6C."
The warm start to winter was largely driven by a stretch of dry, balmy weather early in the month, when Perth recorded three June days above 25C for the first time.
"There were periods when a high pressure system sitting in the bight was directing northerly winds over Perth," Mr Bennett said.
"When that happens, even at this time of the year, warm air from the north gets pulled towards Perth."
Hills drenched, city below average
The Perth metro rain gauge located in Mt Lawley finished with 115.4 millimetres, falling short of its 127.3mm average.
Mr Bennett said not even a rain "train effect" during the weekend, where storm or rain clouds move over the same area, had made up for the dry start to the month.
"Over the weekend we saw some heavy rain in a narrow strip, basically a train effect, which is when the wind regime is set up so that when there's a heavy shower cell or a thunder cell, one after the other will follow in the same direction almost as if it was on a track," he said.
"That's what we got on Sunday with more than 38mm in Perth and 90mm in Bickley."
The 90.2mm Bickley recorded in the Perth Hills on Sunday was its second-highest daily total for June on record.
As a result, it ended up with almost double Perth's total for the month, notching up 224mm and exceeding its 197.6mm average.
WA continues hot, dry trend
It was also the hottest June on record for the state as a whole, with its mean maximum coming in at 2.52C above average.
On the rainfall front, the state was 66 per cent below average, placing June 2020 as the 10th driest in the record books.
"It was below to very much below average for most of the state, particularly through the eastern Gascoyne, Goldfields and Eucla. There we saw some monthly rainfall totals below 10mm," Mr Bennett said.
"The lower west, which is where Perth sits, and the south-west districts were the wettest areas. We saw rainfall totals between 100 and 200mm, and in excess of 220mm in some isolated locations."ABC