Understanding Australia's hottest September on record

Julie Michelle Arblaster, Eun-Pa Lim, Harry H Hendon, Blair C Trewin, Matthew C Wheeler, Guo Q Liu, Karl Braganza

Research output: Contribution to journalArticleResearchpeer-review


September 2013 was Australia’s warmest September since records began in 1910, with anomalous heat across most of the country. Maximum temperatures, averaged nationally, were 3.32°C above the 1961–90 average—the highest anomaly for any month on record and almost a full degree ahead of the previous September record set in 1980 (Bureau of Meteorology 2013b). September marked the peak of a record warm period for Australia, which commenced in mid-2012. The most unusual heat began from the last week of August 2013 and continued into the first half of September. Temperatures moderated from 10 September before extreme heat returned to northern and eastern Australia in the final week of the month. Lewis and Karoly (“The role of anthropogenic forcing in the record 2013 Australia-wide annual and spring temperatures” in this report) determine that the attributable risk of such extreme heat in September has increased five-fold due to anthropogenic climate change. Here we take a different attribution approach and use multiple linear regression and experiments with a seasonal forecast system to explain and understand the magnitude of the September 2013 temperatures.
Original languageEnglish
Pages (from-to)S37-S41
Number of pages5
JournalBulletin of the American Meteorological Society
Issue number9
Publication statusPublished - Sep 2014
Externally publishedYes

Cite this