Perth may soon be having its wettest start to winter in six years, with another rain-bearing front on the way for Western Australia in the middle of this week.

A cold front passing over the Indian Ocean will reach Western Australia by Wednesday, brining a burst of rain, wind and storms to southwestern districts.

Rain ahead of and with the front is expected to spread over parts of the South West Land Division during Tuesday night and Wednesday, bringing widespread falls of 5-10mm.

Some areas near and south of Perth could receive heavier totals in excess of 20mm, particularly with thunderstorms.

As of 9am on Monday, Perth had collected 98.2mm of rain so far this month. While this is well below its long-term June average of 173mm, it's already more rain than the city received during the entire month in 2017 (88mm), 2014 (94mm) and 2013 (44mm).

This week's rainfall is likely to push Perth&'s running monthly total above 100mm and could make this the city's wettest June since 2012, when 141mm was recorded.

Drier weather will return for Perth for the end of the week, although another front is expected to bring further rain and storms early next week.