Describe wind, rain, frost and snow.
Snow: Solid water in the form of snowflakes that falls to the ground from mixed clouds. Precipitation composed of large amounts of white, opaque ice crystals (snow crystals) and their polymers (snow masses). Snow is a natural phenomenon in which water condenses in the air and then falls, or refers to falling snow; snow is a form of water in a solid state. Snow only appears under the influence of very cold temperatures and extratropical cyclones, so the chances of snowfall in subtropical and tropical areas are slim.
Frost refers to the air close to the ground that is cooled to below the frost point (meaning the dew point is lower than 0) due to the influence of ground radiation cooling, and white ice crystals that condense on the ground or objects. Frost is a weather phenomenon that belongs to China's ground meteorological observations. "Frost" usually occurs in the fall to spring time period. In meteorology, the first frost in autumn is generally called "early frost" or "first frost", and the last frost in spring is called "late frost" or "final frost"; the interval from last frost to first frost is period is the frost-free period.