Have you ever been delayed trying to scrape your windscreen while you defrost your car?
Have you ever noticed how some mornings it seems easier to scrape the frost from the car than others. The reason behind this is to do with something called the dew point.
The dew point is the drop in air temperature required for dew to form. When the dew point is below freezing a frost will form and if a surface is wet, ice will form.
The lower the dew point the less moisture there is available for a frost to form and it tends to have more off a 'flakey' consistency, rather than an icy consistency.
Dew points a little closer to freezing, tend to have more of an icy appearance and it is more difficult to remove frost or ice from your windscreen.
Tonight's dew points will be around minus 4, perhaps even below, which means your windscreen will be easy to scrape in the morning as it will be more like power and should easily come off.
Below is an average range of dew points experienced in the winter here in the UK. The lower the number on any one day, the easier it is to remove the frost from your windscreen.