Meteorologists predicted the southerly buster would hit the city from about 5am on Wednesday, and that's precisely when it swept over Sydney Airport.

Weather-related disasters in the past two decades have killed more than 600,000 people and inflicted economic losses estimated at trillions of dollars, the United Nations said Monday, warning that the frequency and impact of such events was set to rise.

Parts of Sydney are copping the odd isolated thunderstorm on Monday afternoon, but the storms are unlikely to reach the severity of the weekend's tempest.

It's only the second July federal election in Australian history - but the weather signs are good.

Tired of the rain? Get used to it - as four grey and wet days settle in over the city.