Total fire bans have been issued in parts of South Australia and western Victoria on Wednesday. Unseasonable heat and gusty winds ahead of an approaching front and low pressure system will elevated fire danger ratings in both states. South Australia's CFS has issued fire bans for 10 of the state's 15 districts on Wednesday, including Adelaide and the Mount Lofty Ranges. Strong northerly winds and temperatures reaching the high thirties will cause severe to extreme fire danger ratings across most of the state. The highest fire danger ratings in Victoria on Wednesday will be in the state's northwest, where the CFA has issued bans on lighting fires in the Mallee and Wimmera. After setting a new April record high temperature for Victoria on Tuesday (39.3C), Mildura is forecast to reach 38 degrees on Wednesday. The front will bring cooler west to southwesterly winds across South Australia and western Victoria on Wednesday afternoon and night, helping to alleviate fire danger ratings during Thursday. Adelaide is forecast to be more than 10 degrees cooler on Thursday behind the front.