MARQUETTE, Mich. (WJMN) – When temperatures start to drop, grab your ice scrapers because it might get frosty.

Most often during the transitional seasons, frost forms on surfaces like windows, cars, and plants. So, how does frost form?

The processes that create frost are essentially the same as the processes that create dew. The only differences are the temperatures.

“It’s the same process that we see in the summertime, where the air outside has to cool to what’s called the dewpoint temperature and that’s the temperature at which the air is saturated and we’ll begin to see condensation on things,” said Matt Zika, a Meteorologist at the National Weather Service. “In the summertime, that dewpoint might be in the 50s, 60s, or even in the 70s, and on a clear calm night, you’ll walk out in the morning and everything is coated with dew. In the winter time, it’s really the same process that’s occurring, but at that time, the dewpoint temperature is now below freezing. So, on a clear, calm night, as the temperature falls down close to that temperature, the dewpoint temperature, or essentially the frost point temperature, you’ll start to have this formation of frost and ice on cars, roofs, grass, and things like that.”

The air doesn’t have to reach the freezing point for frost to form. On a cold night when the skies are clear and winds are calm, temperatures on some surfaces can get even colder.

“The interesting thing about frost formation is you would think, oh, the temperature has to be below freezing everywhere, but the actual air temperature could be in the mid 30s, 36, 37 degrees and you may start to see frost on objects like your car, rooftops, and even the grass,” said Zika. “And, a lot of that has to do with the fact that the actual air temperature is typically recorded at an elevation of about 6 feet above the ground. So, that allows for more cooling down on the ground. In addition, like your rooftops and car tops and things like that, on a clear calm night, as the radiation cools those objects quicker, they may actually fall below, below freezing versus all the surrounding air.”

Although frost happens mostly during the transition seasons, like fall and spring, frost can happen year round in Michigan’s Upper Peninsula. Close to freezing temperatures, clear skies, and calm winds are the biggest factors in frost formation. Terrain and the moisture of the soil can also factor into the equation.