Winter doesn't officially start for two more months, but people across the Midwest got an early taste of the season when temperatures dipped to around freezing, leaving the ground -- and vehicles -- covered in frost Monday morning.
As the cold weather continues to tighten its grip across the country, those mornings when we wake up to find a layer of frost on our windshields will become a common sight. But what exactly causes this phenomenon?
It takes three factors: cold air, clear skies and calm conditions, according to Kendall Wilson, a meteorologist at WLNS in Lansing, Michigan.
Clear skies maximize the effect of the overnight cooldown, allowing the day's heat to quickly escape into the atmosphere, which allows moisture to turn into frost more quickly.
Overnight temperatures also matter. Wilson said the general rule of thumb is when temperatures are between 29 and 32 degrees, the frost is easy to scrape off. But once temps drop below 25 degrees, that layer of frost will be much harder to remove, she said.
Strong winds or overcast conditions can disrupt the freezing process, which is why calm conditions are an important piece of the frost puzzle, Wilson added.
You might notice that your car is covered in frost, but other objects in your driveway are frost free. That's because materials in your car, like metal and glass, cool faster than the surrounding air at night. As water vapor in the atmosphere cools, it condenses onto cooler surfaces like your windshield. When overnight temperatures drop, the moisture turns into frost as the condensed water begins to freeze.
While some frost can easily be removed with deicer and your windshield wipers, colder mornings can leave a thicker layer that requires more elbow grease to scrape off. But there's a solution: If you hate cleaning off your windshield, you can buy a frost cover -- which covers your windshield like a blanket and blocks frost from forming on the glass.