Heavy snow and black ice triggered accidents and caused the closure of major routes in the Blue Mountains and elsewhere in the state.
The Bureau of Meteorology also issued a severe weather warning for damaging winds and blizzard conditions for regions including the Sydney Metropolitan, Hunter and Illawarra.
Live Traffic NSW reported on social media site Twitter that the Great Western Highway between Bathurst and Lithgow and the Snowy Mountains Highway between Bemboka and Nimmitabel had reopened after being blocked.
Travellers between Katoomba and Wentworth Falls were earlier urged to drive with caution because of the ice and snow.
Other areas affected included the Mitchell Highway at Orange, with travellers urged to exercise extreme caution or to delay travel. To the south, the Monaro highway between Bombala and Cooma was also closed in both directions.,
The snowfalls were linked to a cold front that moved through the state on Thursday which was followed by a low-pressure trough, said Rob Sharpe, a meteorologist with Weatherzone.
"That's brought showers with it but because the air is so cold, the showers have fallen as snow across the higher areas of the central tablelands and even the northern tablelands," Mr Sharpe said.
The state's main ski resorts have added to their bumper snow falls, with another 35-40 centimetres falling at Perisher over the last two days, Mr Sharpe said.
Five strong frontal systems over the past month have dumped about 2 metres of snow on resort areas in Victoria and NSW, with some reports indicating sites such as Falls Creek have experienced their deepest snow depths in a quarter of a century.
"But over the next couple of weeks, we're not going to see all that much snow," Mr Sharpe said. "We're going to see a little more high pressure over southern Australia and when (fronts) do come through, they'll be weaker with less cold air associated with them."
For Sydney, Friday looks like being one of the colder days this winter, with a top of 15.9 degrees so far and gusty winds reaching as strong as 61 km/h on the harbour. Those wind speeds should taper off through the day, the Bureau of Meteorology said.
However, the city's generally warm and dry conditions so far this winter should return and remain for another couple of weeks.
"We'll probably crack the low 20s a few times," Mr Sharpe said, adding the city will probably be "not too far off" last July's record average maximums for the month.
In July 2013, the average maximum was 19.5 degrees, or about 3.2 degrees above the long-run average for the city.
So far this month, the average tops are running at 18.5 degrees. Saturday and Sunday are likely to be 16-18 degrees at their warmest, with mostly sunny days of 18-22 degrees stretching out to next Friday, the bureau predicts.
Areas affected by the snow and ice extend to regions in the north, such as the New England Highway between Glen Innes and Armidale, Live Traffic NSW said.
EBOR: Exercise caution on Waterfall Way due to snow and ice. Reduce speed
— Live Traffic NSW (@LiveTrafficNSW) July 18, 2014
To the south, the Snowy Mountains Highway between Bemboka and Nimmitabel was also impacted, with drivers urged to reduce speed.
Back in the Blue Mountains, the Great Western Highway between Mount Victoria and Medlow Bath is also affected, as is traffic in both directions on the Jenolan Caves Road near Hampton.
Weatherzone is owned by Fairfax Media, publisher of this website.