Bureau of Meteorology senior forecaster Tom Delamotte said the chilly Tuesday morning – the equal coldest start to October since 1984 – was a combination of light winds and a dry air mass hovering over the city.
But he said the cold snap would soon pass thanks to hot air over inland Australia, which would be dragged into Victoria by a series of low pressure troughs arriving later in the week.
“There’s a few factors here,” Mr Delamotte said. “There’s the warm air mass, and we’re into the time of year when days are getting longer than nights, so we don’t have as long to cool down.
“And with the days getting warmer, it’s harder to cool down to those chilly starts. We have some northerly winds and a little bit of cloud cover at times assisting in keeping those temperatures a bit higher.”
Tuesday morning was cold, but not 1972 cold, when temperatures dipped to 3.9 degrees in what was an October record for Melbourne.
The warmest first week of October was in 2015, when the maximum peaked at a sweaty 35.8 degrees.