Australia Weather News

Perth has fewer wet days per year, but when the rain does fall, the city often cops it. - ABC

Perth may be best known for its idyllic beaches and sunny skies, but the West Australian capital sees more rain than Melbourne, Hobart and London — cities often associated with gloomy, wet weather.

Perth's average annual rainfall is 733 millimetres, 70mm higher than Melbourne (663mm), more than 100mm higher than Hobart (614mm) and almost 200mm more than London's annual average of 557mm.

The reason? While Perth has fewer rainy days in the year, when it does rain, it pours.

Melbourne, Hobart and London get rain more frequently, but much of the time it is drizzle rather than heavy downpours.

"Perth is very much a Mediterranean climate where we get a lot of rain in winter and late autumn or early spring, but really very little rain otherwise," Bureau of Meteorology (BOM) climatologist Glenn Cook said.

"But when it does rain in Perth we generally get pretty heavy rain.

"One of the reasons for that is the prevailing winds in Perth are coming off the ocean in the wet time of the year, so [they are] bringing a lot of moisture and a lot of heavy rain.

"Whereas for places like Hobart, Melbourne and London, their prevailing winds are actually coming over land for a long way before it gets to those cities.

"So a lot of the rain is actually gone by the time those prevailing strong winds get to those locations."

Winter not the wettest season

Also surprising is the fact that Perth's wettest days are in summer.

"That's because even though it doesn't rain very often in summer, warm air can actually hold a lot more water vapour and generate higher amounts of rainfall," Mr Cook said.

Perth's wettest day ever was February 9, 1992, when the city recorded 120.6mm.

The second wettest was February 10, 2017, when 114.4mm fell in a 24-hour period.

After some much need rain over the weekend, Perth's rainfall total for the month stands at 20.6mm, still well short of the April average of 36.3mm.

The last week of April will bring little relief, with a predominantly warm and dry outlook over the next seven days.

The city's last significant rainfall was on January 16, when a massive 96.2mm was recorded in the wake of Cyclone Joyce.

ABC