The Bureau of Meteorology has issued a severe weather warning for damaging winds and dangerous surf conditions for Sydney.
A deep low pressure system lies over the western Tasman Sea which will lead to cold and wet conditions for the rest of the week.
A large pressure difference between this system and a high to the west will generate vigorous winds and large seas along the coastal fringe today.
Localised damaging winds averaging 65kph with gusts to 100kph could cause damage along the coastal fringe of the Sydney Metropolitan region.
Beach conditions in these areas and for most of the remainder of the coast will be dangerous and people are advised to stay well away from the surf and surf exposed areas.
Wind gusts of 93kph were reported at Little Bay overnight.
The bleak weather is predicted to continue all week with sub 20 degree temperatures and persistent rain.
The final round of the NRL will be played out in cold and wet conditions.
Fans heading to Thursday night's match between the second placed Rabbitohs and third placed Roosters at the Sydney Football Stadium are warned to rug-up.
So too AFL fans heading to the first qualifying final between the Swans and the Dockers at Stadium Australia on Saturday afternoon, facing a top temperature of 19 degrees and a 90 per cent chance of rain.
The State Emergency Service advises people should:
Move vehicles under cover or away from trees.
Secure or put away loose items around your house, yard and balcony.
Keep clear of fallen power lines.
For emergency help in floods and storms, ring your local SES Unit on 132 500.
© ABC 2014
14:16 EDT Sunday saw scorching conditions across Adelaide, in stark contrast to the cool weather during the week.