State of the Climate 2018
Australia's changing climate
Temperature
Australia's weather and climate are changing in response to a warming global climate. Australia has warmed just over 1 °C since 1910, with most warming since 1950. This warming has seen an increase in the frequency of extreme heat events and increased the severity of drought conditions during periods of below-average rainfall. Eight of Australia’s top ten warmest years on record have occurred since 2005.

Number of days each year where the Australian area-averaged daily mean temperature is extreme. Extreme days are those above the 99th percentile of each month from the years 1910–2017. These extreme daily events typically occur over a large area, with generally more than 40 per cent of Australia experiencing temperatures in the warmest 10 per cent for that month.
Fire weather
Fire weather is largely monitored in Australia using the Forest Fire Danger Index (FFDI). This index estimates the fire danger on a given day based on observations of temperature, rainfall, humidity and wind speed. The annual 90th percentile of daily FFDI (i.e., the most extreme 10 per cent of fire weather days) has increased in recent decades across many regions of Australia, especially in southern and eastern Australia.
There has been an associated increase in the length of the fire weather season. Climate change, including increasing temperatures, is contributing to these changes. Considerable year‑to‑year variability also occurs, with La Niña years, for example 2010–2011 and 1999–2000, generally associated with a lower number of days with high FFDI values.

Area average of the number of days with FFDI greater than 25 (very high fire danger) in Victoria in spring for the years starting in July (1978–2017). Although there is considerable interannual variability in the index, there is also a clear trend in more recent decades towards a greater number of very high fire weather days in spring