Carburated airplane engines have a method to cause the carburetor to draw in heated air... the control knob is called... CARB HEAT!!
The process of fuel atomization can cause the fuel/air mixture temperature to drop as much as 100 degrees. So you might imagine there is a wide range of ambient temps where carb icing may occur.
Ice formation INSIDE the carb usually causes a rich mixture.... and can get so rich the engine dies. This often causes distress for PILOTS... and can irritate tractor drivers, too. :-)