What Is Frost? Explaining Icy Winter Patterns

Brrrr … it’s getting chilly out there! It’s fun to walk out in the mornings and see that lovely coating of white frost. But what is frost, anyway?

There are different kinds of frost, depending on how they were formed.

Radiation frost is the most common and is what accumulates on windshields in the morning. We usually just call this type plain old “frost.” It occurs when the weather is calm and cold under clear skies. Clear skies allow surfaces such as windshields and grass to quickly radiate heat out to space. When surfaces cool below freezing, water vapor touching those freezing surfaces instantly turns to ice. In other words, this frost skips the liquid stage and turns directly into a frozen solid. This is called deposition.

Read the rest on Chippewa Valley Family Magazine for some cool pictures.

This article was a challenge to write because, as it turns out, frost is fascinating! I had several directions I was thinking of taking the article, including talking about the dew point and how the frost point is warmer than the dew point (but I couldn’t find a source I trusted that explained this in a way I understood), what the dew point is, and why frost needs very specific conditions to occur. But ultimately, this was originally written for Chippewa Valley Family Magazine for a young audience, and kids would be most interested in the details that they could connect to their real lives. Also, the pictures of types of frost are cool.