What is the name for rain that freezes on contact with a surface?

Rain that freezes on contact with a surface is called freezing rain.

It forms when snow melts into raindrops while passing through a warm layer above the ground, then falls through a shallow layer of air below 0 °C. The drops remain liquid until they touch roads, trees, power lines, or other cold surfaces, where they freeze into a coating of ice.

Freezing rain is different from sleet. Sleet consists of ice pellets that freeze before reaching the ground, while freezing rain remains liquid during its fall. It is also different from hail, which forms inside strong thunderstorms through repeated lifting and freezing.

Even a thin glaze can create dangerous travel conditions and add substantial weight to branches and cables. Weather services therefore treat freezing-rain events as a significant winter hazard, especially when ice accumulates over a broad area.