Editing Monsoon (section)

=== Australia ===
{{main|Australian monsoon}}
[[File:Evening monsoonal squall.jpg|thumb|Monsoonal squall nears [[Darwin, Northern Territory]], Australia]]

The rainy season occurs from September to February and it is a major source of energy for the [[Hadley circulation]] during boreal winter. It is associated with the development of the [[Siberian High]] and the movement of the heating maxima from the Northern Hemisphere to the Southern Hemisphere. North-easterly winds flow down Southeast Asia, are turned north-westerly/westerly by [[Borneo]] topography towards Australia. This forms a cyclonic circulation vortex over Borneo, which together with descending cold surges of winter air from higher latitudes, cause significant weather phenomena in the region. Examples are the formation of a rare low-latitude tropical storm in 2001, [[Tropical Storm Vamei]], and the [[2007 Jakarta flood|devastating flood of Jakarta]] in 2007.

The onset of the monsoon over [[Australia]] tends to follow the heating maxima down [[Vietnam]] and the [[Malay Peninsula]] (September), to [[Sumatra]], [[Borneo]] and the [[Philippines]] (October), to [[Java]], [[Sulawesi]] (November), [[Irian Jaya]] and northern Australia (December, January). However, the monsoon is not a simple response to heating but a more complex interaction of topography, wind and sea, as demonstrated by its abrupt rather than gradual withdrawal from the region. The Australian monsoon (the "Wet") occurs in the southern summer when the monsoon trough develops over [[Northern Australia]]. Over three-quarters of annual rainfall in Northern Australia falls during this time.