The Bureau of Meteorology is warning temperatures could drop by up to 10C as a cold front sweeps over the country.

The weather system is bringing cold and windy conditions from the southern ocean.

Melbourne is set to face its coldest and wettest day of the year with some suburbs to get 30mm of rain today.

The bureau this morning issued a road weather alert for reduced visibility in Melbourne.

"Heavy rain will make road conditions dangerous during Friday in the inner, western, northern, eastern and southeastern suburbs," the weather service said.

New South Wales is also set to feel the chill today, particularly in the west where the first significant cold front of the season is a shock to the system after an unusually warm autumn.

Snow showers are expected in the Southern Tablelands and alpine areas.

The apparent temperature on Thredbo plunged to -17.4C overnight as a cold snap hits southern parts of Australia.

The apparent temperature dropped to 11.6C in Sydney and a chilly 6.5C in Melbourne overnight.

SYDNEY

Partly cloudy with a medium chance of showers, most likely in the late morning and afternoon.

Winds northerly 15 to 20km/h increasing to 25 to 35km/h in the middle of the day then turning north-westerly 30 to 45km/h in the early afternoon. Max: 21C

MELBOURNE

Cloudy with a very high (near 100%) chance of rain, becoming less likely late this afternoon and evening.

Rain heavy at times this morning and early afternoon.

Winds south-westerly 15 to 25km/h tending northeast to south-easterly in the morning then shifting south to south-westerly 30 to 40km/h in the afternoon. Max: 14C

BRISBANE

Partly cloudy with a slight (20%) chance of a shower this evening.

Light winds becoming west to north-westerly 15 to 20km/h in the evening then tending west to south-westerly 20 to 25km/h in the late evening. Max: 27C

CANBERRA

Mostly cloudy with a very high (90%) chance of showers and the chance of a thunderstorm, most likely from late this morning.

Light winds becoming north-westerly 25 to 35km/h in the middle of the day then becoming light in the late evening. Max: 14C

PERTH

Sunny with winds east to north-easterly 15 to 20km/h becoming light in the early afternoon. Max: 25C

ADELAIDE

Partly cloudy with a high (70%) chance of showers, easing to a slight (20%) chance by the middle of the day.

The chance of a thunderstorm and small hail early this morning. Winds south to south-westerly 20 to 30km/h becoming light in the late evening Max: 16C

DARWIN

Partly cloudy with winds south-easterly 25 to 40km/h. Max: 30C

Meteorologist for the Bureau of Meteorology, Mohammed Nabi, told news.com.au more cold weather was on the way for the state.

"A cold front went through (Wednesday) across the state and there is another one on the way. The second cold front will come through today," Mr Nabi said.

"This cold snap is coming through very late this year as we head towards winter," Mr Nabi said. "We have been experiencing abnormally high temperatures for the last few months."