When it's windy, you'd best rug up. Credit:Simone DePeak The wind chill factor makes the "feel like" temperature much cooler than the actual mercury reading. For example, when the temperature is 12 degrees, but there are winds blasting through the city at 60km/h it feels more like 1 degree. So, why does the wind make us feel colder? This time, the answer lies in physics.

Temperate is basically the jiggling motion of atoms, explains theoretical physicist Richard Feynman. When your skin is in contact with still cold air, your skin and the air near the skin eventually reach the same temperature. Essentially, the human body creates a thin insulating layer of warm air around it. But if the warmed air next to your skin is removed by the wind, then you will lose heat. Weatherzone meteorologist Max Gonzalez explains: "Moving air, in this case wind, disrupts this layer constantly replacing it with new colder air. So the faster the wind blows the faster the surface of the body cools and the colder it feels."

So, when Antarctic winds bombard us here in Melbourne, it feels really, really cold. Physicist Michael de Podesta explains it in a little more detail. "Heat is removed from the skin by processes of evaporation, convection, radiation and conduction. For any of these to happen, molecules in the air must bump against the hot (rapidly jiggling) molecules of our skin," he says. "After they've made contact, the air molecules must move away, carrying what used to be our body heat with them in the form of jiggling." In cold weather, the wind tends to be very dry and so the wind will quickly evaporate any moisture on the surface of your skin, making you even colder.

The speed with which your skin cools down depends on the wind speed. The lower the temperature of that wind, the more impact the wind has. This wind chill factor has the same effect as blowing on a bowl of hot soup to cool it down. The movement of the air increases the soup's loss of heat by convection, so the soup cools down faster. You can be outside in 5 degrees wearing a light shirt and jeans in calm conditions with the sun shining. Add a strong southerly wind and suddenly you're needing a coat and gloves. This winter, several cold fronts have blasted their way from Antarctica to Victoria, in rather quick succession. "We have seen really cold winds ahead of these cold fronts, as well as strong winds behind them," says Weatherzone forecaster Kim Westcott.

"It's basically part geography, and part winter and these big cold fronts that are coming off Antarctic waters and off the ice sheet. So the 'feels like' temperature has been and continues to be quite low, especially when those winds start going through the city." Regardless of which direction it comes from, if you've got a very gusty wind, it will feel much colder than just a light, gently breeze, Ms Westcott says. "If the temperature of the ocean is 12 degrees, but the winds are quite strong, the winds coming off those waters will make it feel more like 7 or 8 degrees. It's the same in summer, when you get those gusty north-westerlies before the stormy trough, the city just heats up," she says. It's to do with a constant air flow. "It's like sitting in front of a fan, as opposed to having the fan oscillating around you, or on a lower setting. You are going to feel cooler, if the fan is directly facing you and consistently on your face," Ms Westcott says.