Spring's full bloom will be on show this week in ways that hay fever sufferers will be all too aware.

A much-anticipated cool change took its time making it to Sydney, dragging out another unseasonably hot day.

Sydney is in for a hot few days but the mercury should ease back to milder conditions on Christmas Day.

The mercury dropped to -5.1 degrees on Sunday morning, but it felt even colder, with an apparent temperative of -8.6 degrees just before the sun came up.

Electricity demand surged to its highest in Sydney and the rest of the state for the summer as a burst of inland heat sent the mercury into the low 40s in the city's west.

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

Many of Sydney's commuters are in for a sweltering journey to and from work today as temperatures soar towards the high 30s ahead a late afternoon cool change.

A high-pressure system "as big as Australia" could bring Sydney's warmest patch of weather since April, while most of the country will go for a week with little rain.

A powerful cold front is set to bring 'dangerous' conditions to large parts of south-eastern Australia in coming days and send temperatures plummeting in Sydney.

On a sunny Friday morning grower David McIntyre packed his walnuts and set out from the tiny Victorian town of Stanley to plead with beer giant Asahi to stop buying the water from beneath him.

Time to dig out the electric blanket.

Wild weather across the country has claimed three lives following three incidents of cars being swept away in flood waters.

As global temperatures in this super El Nino year march ever higher, there's one certainty in the chancy world of weather prediction: 2015 will be the hottest year ever recorded.

Coogee Beach looked like a construction site - or a popular holiday destination for heavy machinery - as 12 large earth movers, two vacuum trucks and a crew of 35 worked to restore the beach to its pre-storm glory.

Search-and-rescue teams have located debris appearing to belong to the cargo ship El Faro, which went missing in the eye of Hurricane Joaquin with 33 mostly American crew members aboard more than three days ago.

It was the near miss that went viral after a lightning bolt got strikingly close to a Qantas jet mid-air. A few months later and it has happened again.

The fresh concerns come as nine Lismore residents have dumped flood-affected household items outside Kirribilli House and called on Prime Minister Scott Morrison to act on climate change.

November proved to be a warm chaser to a thirsty October, with temperatures hovering two degrees above average.

Damaging winds and blizzard conditions are forecast for the ACT and region from Monday to Wednesday.

Melbourne could be hit with floods this week as recent rainfall puts pressure on catchments at capacity.

It was a day which saw tops of 39.2 degrees in the city and 40.7 in the west, and ended dramatically with severe thunderstorm warnings across the west.

Three days of heavy rain in mid-April were enough to make it Sydney's wettest autumn in 12 years but conditions have largely dried up since.

The hyperactive hurricane season in the Pacific has jumped up another gear, spawning a record trio of category 4 strength tropical storms that will give the powerful El Nino event yet another boost.

Sydneysiders can expect more rain to fall tonight before it clears to a cloudy but chilly Monday morning.

The restart of Sydney's desalination plant is proceeding faster than expected, helping to slow the drawdown of the city's reservoirs amid the ongoing drought.