Sydney is likely to post one of its coldest weeks of the winter just as the season makes way for a brief but welcome burst of spring.

The city is shivering through its coldest week since early July, including a rapid 10-degree drop in temperatures on Sunday that caught many people on the hop.

A spectator becomes surrounded by whitewash as huge swell pounds the coast. Dee Why. Pic Nick Moir 28 aug 2017 Credit:Nick Moir

The good news is Monday's top of 16.3 degrees may be the lowest maximum for a while. And, after a few days barely reaching the high teens, the coming weekend is likely to much milder including 27 degrees forecast for Sunday.

But a cold front expected to arrive early next week may punish those who prematurely pack away the winter clothes.