Maximums were 3.41 degrees over the norm, with South Australia's out by 5.39 degrees and NSW's by 4.68. Victoria's mean and minimum temperatures exceeded previous anomalies.

Nationally, the warmth broke the previous September mean record by 1.1 degrees.

January baked, Australia's hottest month in its hottest summer. "January was incredibly hot for such a long time for such a large area," said Jones. "In many ways we were very fortunate not to have had a frontal system like Black Saturday (in 2009) to draw down that hot air into a coastal zone with a gale force wind."

Fires destroyed hundreds of properties in Tasmania in January and a similar number in NSW in October. Hot years are now about 2-3 degrees warmer than cool ones 100 years ago. "It's a very large change," Dr Jones said. "That's the equivalent of moving in the order of 300-400 kilometres closer to the equator."

For Australia, the year to beat for heat was 2005, when national mean temperatures were 1.03 degrees above the long-term average. As of the end of November, the country was at 1.25 degrees above the norm. "As best as we can tell, not a single part of Australia has seen below-average temperatures for this year," Jones said.