By JR on Sunday, July 10, 2011
And it's the BOM that says so
Australia has experienced its coldest autumn since at least 1950 for mean temperatures (average of maximum and minimum temperatures across the nation) with an Australian average of 20.9ºC. This was 1.15ºC below the historical average and 0.2ºC below the previous coolest autumn in 1960. It was also the coldest autumn since at least 1950 for Queensland and the Northern Territory.
Large parts of the country recorded temperatures more than 2ºC below the autumn average (figure 1) with about half the country ranking in the coldest 10% of years (figure 2).
The season was marked by consistent below-normal temperatures in most areas, with only a few individual areas recording their coldest autumn on record. These areas were in northern and central Australia including the east Kimberley, the central Northern Territory and small parts of northern Queensland.
The cool conditions experienced in autumn 2011 are largely a result of the strong 2010/11 La Niña event which brought heavy rainfall and cool daytime temperatures to Australia, before decaying in late autumn.
Of particular significance was March 2011 – Australia’s coldest and wettest March on record for maximum temperatures and third wettest month on record (for any calendar month).
Historically La Niña events result in above average rainfall and cooler than average daytime temperatures over large parts of Australia with the historically cold autumns of 1917, 1949, 1955, 2000 and 2011 all occurring at the end of, or during, a La Niña event.