Australia is home to a global hot spot for sea-surface temperatures, with a record burst of prolonged heat in the country's south-east helping to make conditions several degrees warmer than average.

Daily weather charts generated by the US National Oceanic and Atmospheric Administration show the unusual warmth is almost unmatched around the world, compared with normal temperatures.

Crossing the line: (left to right) 10 year olds Bodie Taylor, Arki George, and Frankie Parsons jump in the ocean at Clovelly. Credit:Fiona Morris

Only patches off Greenland and New York in the US are as abnormally warm compared with long-run averages. (See chart below.)

"It's clear sea-surface temperatures around south-eastern Australia, and Tasmania in particular, are well above average," Blair Trewin, senior climatologist for the Bureau of Meteorology, told Fairfax Media.