The sodden and cool end of February masks Sydney's record-breaking summer and the likelihood that autumn will also be unusually warm and dry.

With just a few days of the month to go, Sydney will notch up one of its hottest Februarys in 157 years of records. Added to the city's hottest ever month in January and its second-hottest December, Sydney will cap a summer without peer, temperature wise.

"At the moment, Sydney is running as the hottest summer for nights and days combined, and for nights and days alone," Brett Dutschke, senior meteorologist for Weatherzone, said.

Mean temperatures for Sydney's summer are so far running about 3 degrees above average at 24.9 degrees, well ahead of the previous hottest summer in 1990-91, he said.