Melburnians are preparing for consecutive days of 35° degrees or more for the first time since January.

The mercury is set to hit 35° today, only dipping to 25° overnight.

On Friday it will rise to 38°, with wind gusts up to 45km/h before a cool change early on Saturday morning.

That will bring showers and possibly a thuderstorm before another spell of more mild temperatures next week.

The Bureau of Meteorology says the fire danger will be severe tomorrow in north-west Victoria, where temperatures are likely to top 40°.