The weather for the 2021 Boxing Day Ashes Test between England and Australia at the MCG will very likely defy much of the popular mythology around Melbourne weather.

You know how they say Melbourne has four seasons in a day?

You know how they say if you don't like Melbourne's weather, just wait 10 minutes?

Well there's a lot of truth in those sayings, but for the five days of the upcoming Boxing Day Test, Melbourne's weather looks like it'll be as benign, steady and unchangeable as the first few hours of a Marnus Labuschagne innings.

Image: It's basically going to be "nice", which is not necessarily what you expect from Melbourne weather, or not consistently anyway. Source: Pixabay.

The synoptic situation

The chart below, as it's expected to look on the evening after the first day's play, shows a big high pressure system parked in the Great Australian Bight.

Air moves anticlockwise around a high, which means moist easterlies will affect the NSW, Qld and eastern Vic coastlines. But apart from a light shower or two in east Gippsland, Victoria should remain rain-free.

The pattern really doesn't look likely to change much over the course of the Test. That high is in no great hurry to move east, and there's just enough southerly influence in those easterly winds to keep temps in southern Victoria nice and mild.

The day-by-day forecast

Sunday

The coolest of the five days, with a predicted high of just 20°C and a 20% chance of a light shower.

Monday

Partly cloudy but basically perfect cricket (and spectating) weather with a top of 26°C and a 5% chance of a very light shower.

Tuesday

Rinse and repeat. Tops of 26°C again, and a 5% chance of getting wet although that probability rises to near 100% after 4 pm for spectators in Bay 13 sitting near people with beer.

Wednesday

A maximum of 25°C with a 10% chance of a sprinkle (of rain, not beer).

Thursday

A high of 27°C and in all likelihood, another lovely dry day. That said, there are early indications that a trough located further north could drift down towards southern Victoria, so at this stage, if there's going to be a heavy shower or storm during the Test, Thursday looks the most likely day, with Wednesday in the mix too.

The match result forecast

Not our job, sorry. Instead we leave you with a weather stat:

• Melbourne's average December maximum is 24.2°C.
• London's is around 8°C (depending on which weather station you go off).

We think that's an early victory for Australia right there!