Despite a lot of buzz around a La Nina cycle being declared last week, Bureau of Meteorology forecaster Alex Majchrowski said the predicted overnight drop “isn’t La Nina related”.
“The cold weather is due to this cold front that is making its way across the state,” he said.
A week of rainy days in the mid-20s is forecast to follow the cold snap.
There’s a high chance of showers on Wednesday and thunderstorms on Thursday, both in the afternoon or evening.
Thursday will be the wettest day as a low pressure system comes in through the south of Victoria – up to 10mm.
Temperatures will reach 22 degrees on Wednesday and 25 degrees on Thursday and Friday.
“A La Nina is associated with above average rainfall events – cloudy, wet days,” Mr Majchrowski said.
“Generally your daytime temperatures aren’t as high but your minimum temperatures are higher – it insulates the temperatures.”
Strong wind warnings are in place for Sydney and most of the NSW mid and southern coastline on Monday.
The warnings remain in place for Sydney and the Illawarra on Tuesday.
A severe weather warning is in place for the western side of the Snowy Mountains, including Thredbo, with damaging winds forecast for areas above 1900 metres.
Gusts of 109km/h were recorded before 7am on Monday, with winds in the morning averaging 70km/h.
Mary Ward is a reporter at The Sydney Morning Herald.