A cold front is a common feature on weather maps, especially across southern parts of Australia. We see a cold front when warm air is replaced by cooler air. The cold front itself is the leading edge or the front of the cooler air moving in.

When a cold front passes through we normally see strong winds, rain, and often some thunderstorms. This happens because cold air, being more dense than warm air, pushes underneath the warm air ahead of it, forcing that warm air to rise. As it rises, the warm air then cools, condenses and forms clouds, which can then bring rain and thunderstorms.

A cold front brings a change in wind as well. Usually this is a shift from a warm north-westerly wind that blows before a front arrives – to a colder south-westerly wind that kicks in behind it. This wind shift also causes a noticeable temperature drop.

In southern Australia, the south-westerly winds behind a cold front stream right in straight off the chilly Southern Ocean. And in the middle of winter, these winds, they're very cold.

The heaviest rainfall with a cold front usually happens around the front itself, often falling from a dense blanket of cloud embedded with thunderstorms.

Behind the front, the weather becomes more showery with a mix of sun and showers and in winter sometimes even hail.

Cold fronts can happen at any time throughout the year, but they affect our weather differently depending on the season. In summer they can bring hot, dry conditions and gusty winds, increasing fire risk. Other times, humid air might stream down ahead of a cold front, becoming drier behind it. In winter, cold fronts typically bring strong winds, heavy rainfall, and they are the main drivers of snow and elevated areas of Tasmania, Victoria and New South Wales.

Cold fronts play a significant role in shaping the weather, especially across southern Australia. Understanding them helps us prepare for the weather changes that they bring.