The unprecedented heatwave across southern Australia will come to an end this week as colder air from the Southern Ocean moves over the region, according to weatherzone.com.au On Monday Adelaide will experience the last of 15 consecutive days above 35 degrees, the longest such run since records began there over 120 years ago, and also the longest on record for any Australian capital city. The extended heatwave will end thanks to a cool change, likely to move through Adelaide late on Monday evening before crossing Victoria during Tuesday. A second surge of cold air will sweep across southeastern Australia on Thursday, dropping daytime temperatures below average across much of South Australia and Victoria. Despite the brief spell of cooler weather this week, a number of locations in Victoria and South Australia are a strong chance to set new March average maximum temperature records.