Wind Chill Calculator
What the cold actually feels like once the wind gets involved.
How wind chill works
Your body warms a thin boundary layer of air around the skin; wind strips it away and replaces it with cold air, so you lose heat faster, as if it were colder. The 2001 NWS/Environment Canada formula models heat loss from a face at walking speed: at -5 °C with a 25 km/h wind, it feels like about -12 °C.
What it does and doesn't mean
Wind chill is a heat-loss rate expressed as a temperature; objects and water can't be chilled below the actual air temperature, so your car and pipes only care about the thermometer. Skin is another matter: wind chill is what drives frostbite times, and the formula assumes a dry face; wet skin loses heat far faster still.