Large swathes of NSW have experienced the warmest start to winter in up to 69 years, but those temperatures will come to end this week with a rainbomb set to explode over the country.
Residents in every state and territory have been warned to brace as storms, powerful winds and possible hail are set to hit southern WA before drifting east over the coming week.
Rain is expected to pour over the country for the next seven to 10 days, with the wild conditions predicted to lash the east coast from Wednesday.
Weatherzone has warned of "dangerously foggy" mornings and nights, as pockets of high humidity settle due to lack of winds.
Mascot recorded its warmest day since 2004 yesterday, with 24.2 degrees.
Meanwhile Gunnedah, in the state's north-east recorded 24.7 degrees, the highest June temperature in 69 years.
There is a growing likelihood of an El Niño, with the Bureau of Meteorology (BoM) predicting low rainfall and above-average temperatures in its long-range forecast.
Melbourne can expect a top of 19 degrees today, with morning fog and sunny skies.
A shower or two will develop in both Perth and Adelaide, but it will remain warmer than average, with a maximum of 21 degrees.
Adelaide hit with city's wettest November day in nearly 60 years
Similar conditions are expected for Brisbane with 23 degrees and Darwin, with 31 degrees.
Hobart will feel to brunt of winter, with a chilly 13 degrees forecast, along with Canberra with 15 degrees.
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