It was a bitterly cold night right across Victoria, with subzero temperatures recorded in eight of the nine official forecast districts and numerous readings below freezing in the Melbourne area.

Let's start with Melbourne, where the city itself fell to 1°C, as predicted by Weatherzone. That made it the coldest night of 2024 to date. But the suburbs were much colder, with minimums including:

• Melbourne Airport –0.9°C
• Avalon –0.8°C
• Moorabbin Airport –1.3°C
• Coldstream –3.9°C

Avalon (about 55 km SW of Melbourne CBD) and Moorabbin Airports (nearly 30 km SE of Melbourne CBD) are both quite close to the coast, which illustrates how cold and still the airmass over Victoria was last night – as even a light breeze off Port Phillip Bay would have prevented subzero temperatures so close to the bay.

Coldstream is in the Yarra Valley on Melbourne's northeastern fringe so you'd expect colder temps there, and indeed the weather station has now recorded two consecutive nights with minimums below –3°C. The site's record low is –5.8°C in its 30 years of operation.

Interestingly, Mt Dandenong, at an elevation of 600 metres on Melbourne's eastern fringe, stayed above zero all night and indeed was the warmest place in the Melbourne region between around midnight and dawn

Warmest place in Melbourne is on top of Mt Dandenong (Ferny creek) - classic radiation inversionhttps://t.co/quEgsJrj8D pic.twitter.com/piAQNhCcCI

— Andrew B. Watkins (@windjunky) July 2, 2024

The Dandenong Ranges are known as the closest place to Melbourne to catch a snowflake or two in the coldest weather systems.

So why was Mt Dandenong the warmest spot near Melbourne closest overnight?

Hilly and mountainous terrain is often warmer at night than nearby valleys when a layer of cool, still air is trapped below warmer air. This occurs when you have a cold, stable airmass as we do now, and is called a temperature inversion.

Meanwhile the coldest temperature recorded in Victoria overnight weas –5.9°C at Mt Hotham Airport. This was a fair way off the site’s coldest reading for the year of –8.3°C on June 20.

Image: Victorian temps around 7 am Wednesday, July 3, 2024. Forecast districts are highlighted to show how all were below or close to zero.

But the story of Tuesday night and early Wednesday morning in Victoria was not so much the extreme cold in the mountains where you’d expect it, or the breaking of any records of note.

Last night was all about widespread very cold minimums across the state, and the fact that Melbourne shivered through by far its coldest night of 2024 to date, with more cold nights in store over the next few days as the stubborn high pressure system centred near Tasmania barely moves.