A cool change blew into southwestern parts of the state late on Monday with southwesterly winds gusting to 87km/h at Rottnest Island behind a trough pushing east. This held temperatures down on Tuesday in Perth, only reaching 27 degrees after their 32 on Monday.

This also made for a chilly night over some areas. Busselton fell into the single digits at just five degrees, that's nine below the average. This was also their coldest night since November and in the 12 years of records for February.

Perth also saw a cooler night with the minimum falling five degrees below average to 13 degrees, their coolest night in two months.

As the trough moved further east it brought that cooler change to the remainder of the south coast on Wednesday. Kalgoorlie only reached 27 degrees, 15 degrees below what they saw Tuesday.

This trough will continue to track east, bringing the cooler change to South Australia next. This is also the trough that will grab all of the moisture over the eastern interior and send it further east.