Robert Frost once pondered whether the world would end in fire, or in ice. They weren't heralding the world's end, but this week fire and ice both reared their heads across the state.

"Mate, I lost about 100 heartbeats I reckon in that split second, and got a few more grey hairs."

Canberrans can expect a cool change from Monday after a warm and windy weekend.

NSW will likely cop its third buffeting from an east coast low in five weeks but there is some good news.

Brisbane's sweaty masses are set for a slight reprieve leading into the weekend, with the high temperatures and sticky humidity both set to become that little more bearable.

The Bureau of Meteorology has warned of possible flash flooding in the Queanbeyan and Molonglo rivers on Friday.

If Thursday hits its predicted peak it will be the ACT's longest March heat spell on record.

In a town regarded as one of the world's hottest, Marble Bar locals are still reminded to take care as the mercury hit 48 degrees Celsius on Monday.

Brisbane is in for a wet start to the week, with storms likely to hit the city on Monday and rain predicted for the following four days.

Global temperature records continue to tumble, with August easily the hottest in 124 years of data, Japan's Meteorological Agency says.

Residents in north-eastern NSW advised not to travel as heavy rains from another east coast low lift flood risks all the way down to the Hunter.

The Bureau of Meteorology has issued a severe thunderstorm warning for parts of Sydney.

There are more than 4000 uninhabitable homes across NSW as people begin to wonder what to do amid the mammoth clean-up effort.

Winter's grip will finally feel like it's loosened amid a "heat spike" this weekend - even if that season's squeeze was not a very tight one.

Thunderstorms have rumbled their way across Sydney for the ninth consecutive day, with more thunder and lightning on the horizon throughout Monday morning and into the afternoon.

Sydney's run of balmy weather will take a break as a strong cold front brings a wintry chill to much of the state's south.

Unless you've been inside a 200kmh blast of wind it's hard to imagine the tremendous natural force behind it.

Temperatures are set to climb towards 40 degrees in coming days in Sydney's west with only cooling sea breezes likely to cap the mercury in the city.

Canberrans still wringing themselves out from the wettest June on record shouldn't put away their gumboots just yet.

Growing winds and driving rain from Hurricane Hermine lashed Florida's northern Gulf Coast on Friday as forecasters warned of "life-threatening" floods.