The southwest capital of Perth has struggled to stay above 13 degrees today, and showery gales have persisted through the afternoon. The worst of the Antarctic blast came just after 10 o'clock, when a cold front crossed the city, bringing 100 km/h winds and a temperature drop of over 6 degrees in less than half an hour. Although the city reached 18 degrees early this morning, most of the day has been 13 degrees or less - 5 below average for July. Showers have also been increasing across southwest districts this afternoon. So far 5 to 15 mm has fallen, with similar totals expected again tonight. In fact, when a second burst of cold air pushes through in the wee hours of Saturday morning, snow is possible on ranges above 600 metres and south of about Perth. Conditions will ease over western coasts on Saturday, but persist over southern coasts and spread east towards SA.