South Western Victoria is influenced by the easterly movement of depressions in the Southern Ocean, which have a marked influence on the climate.
A characteristic feature is the rapid change of wind from north to south-west, often in the early afternoon.
|Summer (December-April): Settled weather||In summer and early autumn, winds are mainly from east and south, or south and west. During periods of settled weather, sea breezes become well developed and deflect wind towards the south during the day, often increasing to fresh winds in the afternoon. When a high pressure system passes, hot northerly wind may develop and blow for one to two days. The westerly and south-westerly winds behind the cold fronts blow strong for hours. They might reach gale force and then usually shift to the south before settled weather is gradually established. This pattern generally lasts until the end of April, when the weather becomes less settled.|
|Winter (May-September)||In winter, with the frequent passage of southern depressions, gale force winds from the west and south-west can blow for three to four days and raise heavy seas. The frequent passage of winter depressions also creates heavy south-westerly swells from the southern oceans, which can rise to four to five metres in Portland Bay.|
|Spring (October-November)||In spring, strong westerly and south-westerly winds prevail, raising heavy seas and swells. Wind velocity is generally greater to seaward.|
|Depression||When a depression is approaching with its centre passing to the south, a falling barometric pressure is experienced. If there is a well-defined V-shaped trough, there will be a rapid backing of the wind from west to south-west, with a rising barometric pressure. If the trough of the depression is not well-defined,Â the change in the wind direction is slow with westerly wind and a steady barometric pressure. If the centre of the depression passes to the north, the winds veer north-east through to the south-east or south.|