The most likely place for freezing rain and sleet is to the north of warm fronts. The cause of the wintertime mess is a layer of air above freezing aloft.

Where does sleet occur?

Sleet occurs when there is warmer air closer to the base of the cloud, not the ground. Snow falls through this wedge of warmer air, partially melts and then refreezes as a small ice pellet before it hits the ground.

Which countries have sleet?

Rain and snow mixed, snow that partially melts as it falls (UK, Ireland, Canada, and most Commonwealth countries)