Don't remember where I heard this, but take a typical Minnesota grandfather. Send him outside and ask him what it's like:

Pretty warm -- the mosquitoes appear on air-traffic radar
Nice enough -- pleasent and sunny down through 40F and raining hard
Brisk -- Below freezing and possibly snowing (he may start wearing a jacket)
Sorta chilly -- wind chill below minus 10
Right cold -- actual temperature below minus 20 and/or wind chill below minus 50