How frost can form with temperatures above freezing

This coming weekend will see a dramatic fall in temperatures as a cold front looks to pass Wednesday and Thursday. This could mean some areas of Mid-Missouri falling into the mid to upper 30s. Yet still, some areas could see the possibility of frost.

Frost can form one of two ways. The first occurs from dew on surfaces where the air temperature during the day remains well above freezing, and then the temperatures continue to drop below freezing as the night continues on.

The second occurs through deposition where the dew point temperature of the air falls below zero going from water in a gaseous state straight to a solid in the form of ice on plants. When measuring temperatures for meteorology, most of the time the measurements are taken 1.5-2 meters above ground level. This means that temperatures at the grass level might be a few degrees cooler allowing for the freezing temperature to be reached.