So, what exactly is a wind chill factor?

Posted on January 7, 2014 by 40 Mile Commentator

Somebody left the fridge door open again. Or so goes the old joke. It is January in Alberta and winter seems to already be dragging on as people bundle up to shovel their sidewalks when winds are pushing the wind-chill factor to the -40C range.

This is Alberta and we are a hearty bunch, but December saw the wind-chill push closer to -50. People check the weather forecast to find out what the temperature is and also what temperature it feels like with the wind factored into the equation.

But, what exactly is the wind chill factor, anyway? Well, if you look at the definition provided by Environment Canada, it is the combination of temperature and wind velocity that together gives a perceived temperature. It origins actually go back to 1939 when two Antarctic explorers measured how long it would take water to freeze when placed outside in the wind.

A formula was developed and modified a number of times over the years, but in 2000, Environment Canada held a workshop on wind chill to find a way to better adapt it to reality and adopted an index based on how fast a human face loses heat.

The New Wind Chill formula was put in place after 25 countries agreed it would be the more accurate, easier to understand methodology. The wind chills range from low and moderate to extreme (-45 to -59) and dangerous (-60 or colder).

Using the formula, if the temperature is -25C and the wind speed is 20 km/hr, the wind chill factor would be calculated at -37C.

But, this is Alberta in January and it is cold out. Does it matter if the wind chill is -35 or -45? It is darn cold either way. We’ve been through all this before and know to bundle up in layers, wear our winter boots, use the proper oil, antifreeze, and washer fluids in our vehicles and stay home unless necessary when it gets too bitterly cold out there.

One advantage Albertans have over much of the rest of the country is the chinook winds that we get on occasion to break the cold snaps and not keep us in the deep freeze for months…and I think we are just about due for a good blast of warm air to unthaw things around here.