When to scrape your car

Autumn is finally spreading across the U.S., with more and more frosty mornings in our future. We have some tips to help you cope!

There are two main reasons that your car might need scraping when it's cold out, and that's because of a hoar frost, or frozen dew.

Simply put, this is just what we usually call frost. It is the physical ice crystals that you can see on a sub-freezing object or surface that has come into contact with moist air.

When the surface temperature falls below freezing, and then below the dew point, the water vapor turns directly into ice as it cools and condenses on that surface.

It's a white-ish sort of color, and when you can just use the good old-fashioned windscreen scraper to easily get it off, that's definitely a hoar frost.

Frozen dew on the other hand, will likely take you longer to get off your windscreen. It's a thin coating of glaze ice.

It forms in the same way as regular dew, but in a sub-freezing environment. So, the surface temperature falls below the dew point first, allowing dew to form, and then falls below freezing. So the existing dew on the surface freezes over, and is awfully difficult to scrape off.

Sometimes you can have a layer of frost covering a layer of frozen dew beneath, which then just creates double the work!

It's often in this case that people are tempted to try home remedies, like hot water. Whilst modern wind shields are strong, they can still crack, and the seals can deteriorate faster when subject to rapid temperature changes, so avoid this!

Instead, we suggest a de-icer spray, or a pre-ice spray. Alternatively, you can mix up a concoction of three parts vinegar and one part water, which should keep your screens frost-free by morning. Covers can also do the trick.

But how do you know when to do all of this? Keep an eye on the TemperatureRadar to know when figures may drop into the 30s under clear skies.