A 40 degree temperature spike is normal for December, the Bureau of Meteorology says as the state braces for gusty conditions later today.
"It isn't too unusual to see a run of days in the 20s and then a run of one or two in the high 30s," senior meteorologist Tom Delamotte said.
"We are seeing hot, northerly winds extend across Victoria today. With that are temperatures pushing up into the low 40s.
"That's ahead of a cool change that is going to sweep across the state this afternoon and this evening."
The change will come after a day of total fire ban and likely bring some of the strongest winds of the day across parts of the state.
The change is likely to kick up dust in the north-west of the state, around Mildura, Mr Delamotte said.
There could be a 10 degree drop within the first two to three hours of the change across inland Victoria, Mr Delamotte said. Mild conditions will return for the rest of the week.
The Country Fire Authority has declared a total fire ban in parts of central Victoria on Monday, December 9.
The Northern Country forecast district - which encompasses Bendigo and Echuca - is subject to the ban, as are the Mallee and Wimmera.
Fire danger has been rated as severe for the Northern Country and Wimmera on Monday, while the Mallee is facing extreme fire danger.
Under the total fire ban, no fires can be lit in the open air.
The use of solid fuel barbecues, gas-powered bird-scaring guns, welders, grinders and solderers, bee smokers and incinerators is prohibited.
Vehicles cannot be driven through or across vegetation unless fitted with an efficient silencing device, although even the use of such vehicles in areas of vegetation should be avoided.
People should also avoid using such equipment as lawn mowers, chainsaws and farm machinery wherever possible.
The CFA advises those living in areas of high fire risk to activate their bushfire plans.
"Despite experiencing a mild start to summer, hot, dry and windy conditions are expected tomorrow, with the potential for increased fire activity," Emergency Management Commissioner Andrew Crisp said.
"East Gippsland has already experienced several bushfires, which continue to burn and more than 32,400 hecatres currently on fire.
"Yet it's important for all Victorians to be aware that fires can happen anywhere and without warning.
"We've been ensuring fire agency crews are well prepared, and it's also extremely important that the community is ready, not only for tomorrow, but for the months to come".
Mr Crisp urged people to look after themselves and others who were more vulnerable.
The remainder of the state is forecast to experience very high fire danger on Monday.
Bendigo can expect the daytime temperature to top 40 degrees on Monday, after an overnight low of 16 degrees.
Meanwhile, Echuca will head for a forecast high of 41 degrees.
Elsewhere, Castlemaine is forecast to reach 38 degrees on Monday, Maryborough 39 degrees and Kyneton 37 degrees.
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