"The idea of wind chill indicates how cold it feels on the skin's surface as opposed to the actual temperature," explains Steve Cleaton, forecaster for BBC Weather. "Wind chill relates to a combination of three things - wind speed, moisture content or humidity and the air temperature. Conditions feel coldest on your skin when they are particularly windy and dry. This is because the moisture on our skin evaporates readily in dry air compared to moist air, causing evaporative cooling on the surface of the body. Our bodies work harder to maintain its core temperature, leading us to feel colder."