Towns in northern Victoria face several days of temperatures of 40 degrees or higher, including Mildura, Swan Hill and Echuca.

At 6.17pm, Melbourne recorded 41.1 degrees, just above the city's forecast top of 41. Hopetoun was the hottest place in the state, with 43.9, Ouyen was at 43.6, Mildura 43.4, Swan Hill 42.6 and Horsham was 42.9.

The bureau has forecast mixed conditions in Melbourne, with a maximum of 27 degrees on Saturday, before 31 degrees on Sunday and 38 degrees on Monday. Temperatures will drop to the mid-20s again between Tuesday and Thursday.

The opening night of an outdoor production of Alice in Wonderland at Ripponlea was cancelled due to the hot weather, while the heat affected Melbourne's transport systems.

A cool change passed through Port Fairy Friday evening but Melburnians will have to hang on a bit longer than first thought.

The long-awaited cool change was expected to sweep through Melbourne around 12.30am Saturday morning, a Bureau of Meteorology spokesman said.

Temperatures at Frankston dropped to 29 degrees by 11.30pm and in Geelong, the mercury was sitting on 25 by midnight, 15 degrees cooler than at 8pm.

But the change was predicted to bypass most of the state, meaning many residents still faced an uncomfortable night.

The coastal town of Sorrento was hit by a power outage about 6.30pm, which cut supply to 25,000 homes. United Energy said about 9pm the fault had been fixed and power was being restored.

Bureau of Meteorology senior forecaster Richard Carlyon said the past two summers had been quite wet and that ‘‘we just haven’t seen these temperatures for a while’’.

VicRoads is urging drivers travelling in regional areas to take precautions such as letting others know of their travel plans and arrival times, driving with a full tank of petrol, and carrying plenty of water in case of an unplanned stop.

And while the West Gate Bridge is scheduled to reopen with all lanes by Monday, the Western Ring Road will be closed Altona-bound between the Tullamarine Freeway and Sydney Road on Sunday.

Drivers on the Pakenham bypass on the Princess Freeway will also endure lane closures next week and VicRoads is urging drivers to use the old Princes Highway while travelling through Pakenham.

There is a total fire ban across Victoria until midnight, with the Wimmera, south-west and central regions - which includes Melbourne and Geelong - expecting extreme conditions - only one level below code red.

One Mentone family trying to get cool enough to sleep on Thursday were woken up when smoke started coming through their ducting.

The Metropolitan Fire Brigade believes the house fire was started by an evaporative cooling system.

People trying to cool off in Port Phillip Bay have been thwarted by sewage spill alerts at two locations. Half Moon Bay in Black Rock remains closed to swimmers and the Environment Protection Authority is currently investigating a spill at Portsea.

Mildura will be set for one of its longest consecutive spells of days above 40 degrees, according to the Bureau of Meteorology.

Duty forecaster Michael Halfpenny said the town reached 40.0 on Thursday and has five further days of 40-plus forecast - 44 on Friday, followed by 43, 41, 44 and 43 on Tuesday.That’s six in a row, and if Wednesday’s forecast top of 38 goes to 40 that will be seven. [Thursday’s forecast top is a mere 34].

How does that compare historically? In the horrendous heatwave of January 27 to February 7 2009, which culminated in Black Saturday, Mildura had twelve consecutive days above 40. On Black Saturday itself, it reached 46.7.

For consecutive days in January alone, 1939 still holds the record – nine days above 40, with 39.9 on the tenth day. More recently, there was a run of six consecutive days above 40 in 1979.

And the hottest day ever in Mildura? That’s a matter of some debate. 50.8 – Victoria’s hottest-recorded temperature – was recorded on January 6 1906, but doubts about accuracies of the equipment used lead the Bureau of Meteorology to believe it may have only reached 48.3.

The mercury reached a record-breaking 41.8 in Hobart, while Adelaide recorded its fourth hottest day on record with a temperature of 45 degrees.

With Stephen Cauchi and Nino Bucci