Frost

Frost is the white, icy coating you sometimes see in the morning. It forms on grass, leaves, and car windows when it is very cold. Frost can make beautiful patterns that look like lace or feathers. It usually appears overnight and melts when the sun comes out.

How Frost Forms

Frost forms when the air is very cold and wet. Tiny bits of water in the air turn directly into ice crystals. This happens on surfaces that are colder than the freezing point. Clear nights with no wind are best for making frost. When the sun rises, the air warms up and the frost melts away.

Frost and Plants

Frost can hurt plants and crops, especially in the spring. Farmers worry about frost when their fruit trees are blooming. A hard frost can kill young plants and damage fruit. Some farmers cover their plants or spray them with water to protect them. Plants that live in cold places have special ways to survive frost.

Fun Facts

• Frost can form even when the air temperature is above freezing if the ground is cold enough.
• The first frost of fall is called a 'killing frost' by gardeners.
• Jack Frost is a character in old stories who brings frost to the world.

Did You Know?

Hoar frost makes amazing feather-like shapes on plants and fences. It forms on very cold, calm nights and can grow crystals over an inch long.