What does frost mean in the weather forecast?

The weather forecast frost model is as follows:

The formation of frost is the ground condensation phenomenon on water vapor objects near the ground, which is mostly formed on sunny days, which is often called "thick frost is fierce in the sun"; It also forms at night, and in a few cases, when the sun sets before sunset, frost can also begin to form.

Usually, the frost will melt soon after sunrise, but it can last all day in cold weather or shady places. The formation of frost also requires two basic conditions. First, the air contains more water vapor; Second, there are objects below zero.

Extended data

To make matters worse, as another natural phenomenon, a layer of frost sometimes condenses on the snow on the ground or features. This often happens from night to early morning when the rain and snow turn fine. When the ground temperature reaches 0℃ or below, under the combined action of cold advection and strong radiation cooling on the ground or snow surface, the temperature drops, often appearing extremely low, which will do harm to field crops.

But relatively speaking, where there is snow, there are many gaps in the snow, which is a bad conductor of heat and has a counter-diffusion effect on the heat in the soil. Frost formed on the snow surface can also release some latent heat when water vapor condenses into ice crystals, which is relatively less harmful to overwintering crops. On the contrary, the frost on the surface of crop stems and leaves without snow is more harmful because of radiation cooling.