After bringing record breaking heat to WA, the sizzling air mass is fanning across South Australia. Clear skies and gusty northerly winds brought rapid heating to Adelaide today, with the mercury tipping 40 degrees by 11am and 44 just after 2pm. This makes it Adelaide's hottest day in four years. So far it is also the hottest day since the summer of 2009 for Whyalla, Edithburgh and Hindmarsh and Parafield, which have all reached the low forties. This heat comes after record breaking temperatures were recorded in WA on Thursday. The town of Eucla reached 48.2 degrees, 22 degrees above average and their hottest day on record. Meanwhile, a blistering 49 degrees was recorded at Red Rocks Point in the Eucla district. Back in SA, these hot temperatures are combining with extremely dry and gusty winds to cause dangerous fire conditions. Relatively humidity has remained below 5% across much of the state and northerly winds have been gusting to 40-50km/h in some places. This had led to catastrophic fire ratings for the Mount Lofty Ranges, Kangaroo Island and the Lower South East, while a fire on the Yorke Peninsula has recently been contained. An approaching low pressure trough will sweep across the state's south this afternoon, reaching Adelaide by early evening. This will bring a gusty but dry southwesterly wind change, with a noticeable drop in temperature. For Adelaide, Saturday won't be nearly as hot with a top of 31 degrees, however the heat is set to return on Sunday with temperatures forecast to reach the high 30s or low 40s each day until the end of next week.