If there's one thing we know about Melbourne weather, it's that it is predictably unpredictable and reliably unreliable. Wait five minutes if you don't like the weather, and all that.

And the Victorian capital was up to some of its finest tricks on Tuesday night, with a reading of 19.4°C at midnight, after the mercury had reached just 15.8°C at midday on Tuesday.

Yes, Melbourne was 3.6°C warmer in the middle of the night than in the middle of the previous day.

Why?

It was all thanks to relatively warm air being pushed across the city from the north ahead of a cold front. Cloudy skies also contributed to a night was much warmer than you'd expect in April.

• Melbourne's average April minimum is 10.8°C
• Last night, the officially recorded minimum was 16.8°C, but temps only dropped after dawn as the cloud moved away.
• Indeed, it was still as warm as 20.0°C at 5:20 am this morning.
• It won't get much warmer than that today, with showers and a top of 21°C forecast

Meanwhile Sydney is also in the throes of a summery mid-April burst, as the warm air tracks eastwards. Top temps of 29°C are on the cards, and the harbour city had already reached 24.1°C by 10:30 am.

We're here to provide meteorological infomation, not culinary suggestions, but our strong advice to Sydneysiders is to eat lunch outdoors today.