Why Frost Forms on the Outside of Cold Drinks

Frost forms on cold drinks because the glass cools the nearby air below freezing.
Water vapor in the air condenses first, then freezes into tiny ice crystals.
The process is called deposition—gas turning straight into solid ice.
Humid air makes more frost, while dry air produces little or none.
That’s why frosty mugs are common in summer when humidity is high.
The colder the drink, the thicker and faster frost builds outside the glass.
Frost on drinks is the same principle as frost on windows and car windshields.
Condensation plus freezing is nature’s double act in creating the frosty look.
Insulated cups prevent frost by keeping the outer surface warmer.
That sparkling frost is really the air’s hidden moisture turning solid before your eyes.