We’ve heard it before, those in older generations say the wind chills were always much lower when they were kids compared to today. But was it really? The wind chill calculation has gone through changes so it was probably not as cold as we were once told.
First, what exactly is it? Our bodies lose heat naturally to the environment around us – that’s convection. Here we have a scenario (below) where it’s 20° outside with no wind. Little or no wind will help keep the heat inside our bodies longer. With no wind, that means 20° feels like 20°.
If we have the same temperature of 20° (graphic below), only now we increase the wind to 20 MPH, that changes everything. The moving air will break up our insulating warm later which takes heat from our bodies quicker. So with this 20 MPH wind, that 20° air feels like 4°.
But it isn’t just about feeling cold, there’s something even bigger that could be happening. When you’re exposed to extreme cold, most of your body’s heat will go to your core to protect your vital organs. The lack of circulation in your extremities like your fingers, toes, and nose will cool them even faster and allow for the skin and underlying tissue to freeze. This is frostbite and it’s permanent and irreversible.
That’s why the wind chill chart was constructed to give you more insight into what your surroundings could do to your body. This chart was made in 2001. It gives the wind chill and the time it would take for frostbite to start. So a -15° air temperature with a 20 MPH wind will give us a wind chill – or a feels like – temperature of -42°. This means frostbite can begin in as little as 10 minutes. Before 2001, we had a wind chill chart but it wasn’t as accurate as.
This curve (below) shows the differences between the old wind chill chart and the newer one. This means some of the wind chills we saw as a child were not as cold as we thought, they were just calculated differently. The top line is where the wind chills are now and they’re much more accurate.
The old wind chill chart said that a 5° temperature with a 30 MPH wind would give a -41°wind chill. But the newer wind chill chart is more accurate, it says the same temperature and wind give a -19° wind chill. One would trigger a wind chill warning one wouldn’t.