CFA crews extinguished a boat fire after it mysteriously went up in flames at Lake Charlegrark

Three CFA tankers raced to the fire around 11:47am on January 1 and were able to extinguish the burn without any injuries to civilians or first responders, and without the blaze spreading to nearby vegetation.

A CFA spokesperson told The Wimmera Mail-Times the damage to the speedboat was so severe that the vehicle was now classified as a write-off.

Police are investigating how the fire began.

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The blaze came in the wake of a particularly scorching start to the new year for the Wimmera district, where temperatures peaked at 38 degrees on Sunday afternoon in Horsham.

There were similarly sweltering conditions in Edenhope, where the mercury hit 37 degrees after midday.

A High Fire Danger rating is in place for the remainder of the week, with temperatures expected to jump to the high 30s around the district once again this coming Sunday.

Fire restrictions will also remain in place for the week, with the CFA urging Wimmera residents to abstain from various potentially hazardous activities.

CFA Horsham commander Lindsay Barry said it was still too early to determine whether a total fire ban will be announced this weekend.

"As good as my crystal ball is, it's hard to determine this far out whether it will be a total fire ban. What we do know about the weather that's upcoming is the temperature will increase," Mr Barry said.

"In order for it to be a total fire ban we need a combination of high temperatures and wind, and it's just too hard to forecast what the wind's going to be like this far out."

Mr Barry urged Wimmera residents to stay updated on changing conditions and restrictions ahead of this weekend's soaring temperatures.

"Total fire bans are declared the day prior, so it's important people keep a view on where they source their information from so they've got a timely record of what they need to know," he explained.

"The fire danger will increase with the high temperatures, so it's important people in communities seek out information online or other platforms to stay informed, and as always act on that information as it comes forward."

While the Wimmera district has not seen a total fire ban in the past 12 months, the Mallee district announced its first ban in months on Monday, with restrictions being lifted at midnight.

A list of restrictions and updates on the fire rating can be found at the CFA website.