It might be hard to recall after the past few days of torrential rain, but December has been hot – the records don't lie.

The extreme heat prompted the Bureau of Meteorology to issue a Special Climate Statement, confirming record temperatures across South Australia, NSW, Tasmania and Victoria, where the highest daily minimum temperature ever recorded was reached (31.9 degrees in Mildura).

"The most intense phase of the heatwave began on December 16 as high pressure became established in the Tasman Sea and directed hot, north-easterly winds over South Australia," the bureau said.

"The heat spread over much of south-eastern Australia from 18 December as winds turned more northerly, reaching its most intense levels over the weekend of 19-20 December. A trough and cold front crossed the region on 20 December, bringing the heatwave to an end over the most-affected areas although hot conditions continued over parts of New South Wales on the 21st."