Temperatures will soar across Victoria today, with fire bans and heat health alerts issued across the state. Northerly winds will draw hot air from the nation's interior across Victoria today, causing temperatures to exceed 40 degrees in all of the state's nine weather districts. Some parts of Victoria are forecast to experience their hottest day in three to four years, including Horsham (45C) and Wangaratta (43C). Today's forecast maximum temperatures in Melbourne (42C), Werribee (42C), Sale (41C) and Bairnsdale (41C) are at least 15 degrees above average for this time of year. Melburnians had a restless start to the night, with the temperature still 32.2 degrees at midnight. While conditions became cooler early this morning, the rising sun is now quickly reheating the city. The mercury should be back up to 30 degrees in Melbourne by around 9am and pushing into the high thirties at midday. If the city exceeds 42.2 degrees this will be its hottest day since 2014. It will be another hot day for competitors and spectators at the Australian Open. Total fire bans are in place today for all of central and western Victoria except for the Northern Country district. The Department of Health and Human Services has also issued heat health alerts for six districts today. A cool change will move into southern Victoria this afternoon, reach Melbourne during the late afternoon/early evening before moving further inland overnight. While the change will bring relief from the heat across southern Victoria at the end of a hot day, the shift in wind direction could be problematic for any fires that are burning in the region. There is also a chance of the odd thunderstorm in northwest Victoria from later this afternoon. If they do form, lightning and blustery winds may exacerbate the fire danger in parts of the Mallee and Wimmera districts. Cooler conditions will return to southern Victoria this weekend behind the change, although temperatures will reach the forties in the state's north once again on Saturday and Sunday.