For the benefit of those who might not be familiar with the term, and in keeping with a Winter theme (though the weather here in Toronto has been unseasonably warm all Winter so far), let's talk about "wind chill". When you check the weather in the morning, trying to decide what to wear and all (see previous post), you'll hear something like, "It's currently 3-degrees, minus 2 with the wind chill."
What that means is the actual temperature out is 3C, but what it "feels like" (because of the wind) is -2C.
According to our friends at Wikipedia: "Wind chill (often popularly called the wind chill factor) is the felt air temperature on exposed skin due to wind. The wind chill temperature is always lower than the air temperature, and the windchill is undefined at the higher temps (above 10 °C [50 °F])."
You always want to dress for the wind chill temperature. Even though here in the city there are corridors where you can avoid being exposed to the wind, if you go out, you can't entirely avoid it. And when the chill is below -19C, exposed skin can freeze in 30 minutes.
Take wind chill seriously and remember to dress warm!