The Bureau of Meteorology website provides an overview of Australian climates (external link). This includes Australia-wide maps of Major Climatic Zones.
Victoria’s climate is generally favourable to plant growth, providing a combination of adequate rainfall and warmth, in most parts of the State. In winter, growth may be restricted by lower temperatures, whilst in summer, rainfall may be insufficient to meet plants’ demands for water. If irrigation water is available in summer then the productivity of pastures, crops, orchards and vineyards can be high as plants grow vigorously through long days of sunshine and warm temperatures. The climate of Victoria is influenced by seasonal weather patterns as well as topographic features.
Victoria differs from other mainland Australian States in that it lies furthest South and has its major mountain ranges running east-west rather than north-south. Its southerly position and maritime influence have a moderating effect on climate, which is particularly evident in winter. Snow rarely falls at altitudes below 600 metres. To the west and north of the Great Divide the land flattens out to the dry inland plains. It is in the Mallee where the highest temperatures in the state most commonly occur during summer, and where the annual median rainfall drops below 300 mm.
The coastal strip, south of the ranges, is generally wetter except for areas around central Gippsland and to the west of Melbourne, where hilly terrain upwind reduces the effectiveness of rain-producing systems. Rainfall here drops below 600 mm.
The weather of Victoria is primarily influenced by weather patterns originating in the Southern Ocean. There is a general west to east movement of high pressure systems across or north of Victoria throughout the winter months from April to November. These high pressure systems are interspersed with low pressure systems or cold fronts which bring moist airstreams and showers or rain to many parts of Victoria. When these systems link with tropical moisture from the north, rainfall can be significant, even over the dry northern plains.
In Spring, weather systems are more mobile and the location and extent of anticyclonic cells is more variable. This results in Victoria’s weather being more variable from September to November, compared to the winter months.
During the summer months from December through March, high pressure systems from the Southern Ocean move further south. Warmer conditions are moderated by the passage of cold fronts which are associated with cooler southwesterly changes and isolated showers in the southern half of Victoria. Thunderstorms or the influence of tropical systems to the north can provide significant rainfall in certain circumstances.
El Nino Influence
Victorian climate conditions are also influenced by the ocean-atmosphere system in the tropical Pacific. The El Nino phenomenon is a disruption of this system which affects the normal climatic patterns in some years. Further Information on El Nino worldwide can be found on the El Nino Theme Page (external link) (U.S. Department of Commerce/National Oceanic and Atmospheric Administration/ Tropical Atmosphere-Ocean Project).
The Bureau of Meteorology (BOM) website has an El Nino Wrap-Up (external link) page which provides the current status of El Nino conditions in Australia as well as background information about El Nino. Analysis of previous El Nino events (external link) is also provided on the BOM website.
Source: Climate of Victoria, Bureau of Meteorology (1993). Published by Australian Government Printing Services. Commonwealth of Australia. Copyright. Reproduced by permission.
Atlas of Victoria (1982). Government of Victoria