Today is the first day of Australia's coldest month of the year.

While the shortest day of the year - the winter solstice - occurs in late June, Australia's coldest month is actually July.

Australia experiences its fewest hours of direct warming from the sun around the winter solstice. However, the oceans surrounding Australia don't reach their coolest state until several weeks after the solstice, typically in late winter or early spring. This is because the ocean is efficient at retaining heat and it takes longer to cool down than air.

Image: A foggy morning in Bena, Victoria. Source: @craigando2 / Instagram

The lag in ocean cooling causes July to be the coldest month of the year in Australia based on average minimum and maximum temperatures. And this isn't just the case for Australia area-averaged temperatures. Every state and territory capital city also experiences their lowest long-term average maximum and minimum temperatures during July.

With Australia's air temperatures taking a dive in July, this is also a time of year we typically see snow depths ramping up in the alps. The average peak snow depth for Australia's ski resorts usually occurs in late August or early September.