What is frost?

Frost is the condensation phenomenon of water vapor (that is, gaseous water) at a very low temperature, which is very similar to snow.

On cold winter mornings, outdoor plants usually frost. This is because plants dissipate heat slowly at night, the ground temperature is particularly low, and the water vapor is not emitted quickly. When it still gathers on the surface of plants, it will freeze and form frost.

Scientifically speaking, frost is made up of ice crystals, similar to dew. When the relative humidity in the air reaches 100%, water is separated from the air. The only difference between the two is that the dew point (the temperature at which water vapor liquefies into dew) is higher than the freezing point, while the frost point (the temperature at which water vapor condenses into frost) is lower than the freezing point, so frost will only appear when the temperature near the surface is below zero degrees Celsius.

In which season does frost appear?

Frost usually appears in autumn, winter and spring. The solar terms "first frost", "first frost" and "First Frost" are not the same thing, but three different concepts. "Frost" refers to a kind of white ice crystal condensed by water vapor on the ground in cold weather; "Frost" refers to a common agricultural meteorological disaster phenomenon; The "first frost" solar term refers to the season that reflects the sudden drop of temperature.

The first frost is the eighteenth of the twenty-four solar terms, the last solar term in autumn and the transitional solar term from autumn to winter. Every year on the 23rd or 24th day of Gregorian calendar 10 year 10, the first frost solar term is when the sun moves to 2 10 degrees of the longitude of the Yellow River. The temperature is low at this time, so get up in the morning and open the window. On the roof, flowers are white. This is Frost.