WRAL WeatherCenter Blog

I was wondering if just because it gets below 32 degrees does that mean its gong to frost such as tonight is supposed to get 29?

Posted March 16, 2008 10:22 a.m. EDT

MIKE MOSS SAYS:       Ashley,      A temperature below freezing does not automatically mean that frost will form. In addition to the temperature of an object falling to freezing or below, there must also be enough moisture in the adjacent air to become saturated and cause water vapor to deposit out of the air and onto the cold object in the form of ice crystals. If the air is too dry for that, subfreezing temperature can occur without the formation of frost. For a little more in the subject, see an earlier post located at