Fires breached containment lines in two NSW locations on Sunday morning as temperatures climbed above 35 degrees in parts of the state and Sydney.

It was a day which saw tops of 39.2 degrees in the city and 40.7 in the west, and ended dramatically with severe thunderstorm warnings across the west.

Sydney is in for gusty winds on Wednesday, followed by chilly temperatures next week as Winter makes itself known.

Queanbeyan and Molonglo rivers have been issued a severe weather warning and remain on flood watch.

Sydney may be scorching right now, but be warned - the worst is yet to come.

A Kiama drone operator has told of his urgent efforts to raise the alarm after a shark made an unexpected appearance in his video, coming disturbingly close to unaware surfers.

The mercury dropped to -5.1 degrees on Sunday morning, but it felt even colder, with an apparent temperative of -8.6 degrees just before the sun came up.

While the dry,calm, and mostly sunny days are making it seem that summer will never end, its demise is in sight.

May and autumn will come close to being a record warm ones for Sydney, the state and the rest of Australia as the giant El Nino added a hot overlay to temperatures that are rising in the background here and in most parts of the world.

Monday morning's grey drizzly skies will usher in a warmer than average work week, before a turn for the chilly on Friday.

Wednesday night may be on the cool side for Queensland visitors to the opening State of Origin match at Homebush but the overall conditions could hardly be better for football.

The Earth is in the midst of an usually long spell between ice ages and the build-up of carbon dioxide emissions through the burning of fossil fuels may postpone the next glaciation event by at much as 100,000 years, according to new climate research.

Canberrans spent much of Valentine's Day looking for ways to cool off and beat the heat as the capital sizzled.

Sydney is in for a hot few days but the mercury should ease back to milder conditions on Christmas Day.

Sydney will likely come close to notching its hottest day this late in the summer for 12 years - and there won't be much early relief.