The Mallee Natural Resource Management (NRM) Region is described as having hot, dry summers and cold winters. There is spatial variation in temperature within the Mallee, with the north experiencing average maximum temperatures that are around two degrees warmer than the south of the region (BoM 2012).
The Bureau also identifies the region as lying within a seasonal rainfall zone, characterised by a wet winter and low summer rainfall based on a 100 year rain record between 1900 and 1999 (BoM 2012). The semi-arid nature of the region is evident from the high levels of annual evaporation (seven times the average annual rainfall). As with temperature, there is spatial variation in rainfall within the Mallee, with annual rainfall totals in the south higher than those in the north-east.
Recent examples of weather extremes in the Mallee include the “Millennium Drought”, which had severe impacts on the region between 2002 and 2010; and the La Nina rains of the 2010/11 summer that followed the drought and caused significant flooding and widespread property damage. Other weather extremes can occur in relation to frost, hail, temperature, and wind events.