A typical "winter" storm that blew through Western Australia's South West at the start of summer has brought with it two months' worth of rain and wind gusts of more than 100 kilometres an hour.
Bureau of Meteorology duty forecaster Bob Tarr said storms of this intensity were often seen in winter, but it was rare to have them track this far north in summer.
"The same intensity storms do exist but they tend to be well south over the Indian Ocean and Southern Ocean," he said.
"As it just turned out the jet stream came further north. The centre of the low pressure system passed just south of Albany along the South Coast and the actual cold front itself pushed well up through the central west of WA.
"We basically just had a winter storm in December."
Emergency crews received dozens of calls for help overnight, but most were for minor roof damage.
Western Power called in extra crews to deal with pockets of power outages across its network.
The deep slow-moving low pressure system is tracking eastwards near the south coast and is expected to start to ease this afternoon.
Double the average rain in a day
Cape Leeuwin recorded winds of 106kph about 6.00pm on Sunday, and in the metropolitan area gusts came close to 90kph.
Perth has well and truly exceeded its average December rainfall, recording 19 millimetres in Mount Lawley. The average for the month is 10.1mm.
The city is now set to reach its total annual forecast rainfall for the first time since 2011.
There were heavier falls further south with Jarradale recording 36mm and 26mm in Bridgetown.
Rain forced play to be abandoned on day four of the third Ashes Test on Sunday, and although there is more rain expected today, most of it is expected to have passed by mid-morning.
The storm also forced the cancellation of a number of major events in Perth, including Carols by Candlelight and A Day on the Green.
Fear not, summer will return
Mr Tarr said the storm had now largely blown through and the State would return to normal, warmer early summer weather over the next few days.
"By the time we get to the middle of the week we're getting close to normal temperatures for Perth and then back up to the low to mid-30s by the weekend so it's really just a brief interruption in the summer," he said.
"This time of year it's hard to keep temperatures cool for very long.
"It's really hard to predict these one-off occurrences more than a few days out but you'd think this would be the only time this would happen during the summer."