In the country's south, South Australia and Victoria will be heating up today, the last day of such heat for about two weeks. For most areas it won't be as hot as it got in the last few weeks because the hot airmass over central Australia is losing its intensity. The hot air is being drawn into the southern states courtesy of northerly winds. Adelaide can expect a top of 38 degrees today. Melbourne is set to reach 36 degrees and Mildura 40 degrees. Low humidity and high temperatures bring an increased risk of fire danger to these states. A total fire ban is in place for the South West district in Victoria. In South Australia, extreme fire danger is forecast for the North West Pastoral, West Coast and Lower South East districts. It will be a warm night ahead for both states. Around bedtime, it will have only cooled 33 degrees in Adelaide. Melbourne may still be 30 degrees at 9 pm tonight. A cool southerly change will bring relief from the heat. This change is not due until early hours of Friday morning for Adelaide. In Melbourne, this cool change will arrive later on Friday morning, bringing gradual cooling throughout the day. Heading into the weekend, temperatures will remain below average with mostly sunny conditions for Adelaide. In Melbourne, temperatures will be in the low twenties for Saturday and Sunday with a shower predicted later in the day on Sunday. This will herald a run of cooler-than-normal days and nights which should last a week or even longer.