How many degrees below zero will it snow?

It will snow when the temperature is below zero.

There are two conditions for snowfall: first, water vapor saturation; Another condition is that there must be condensation nuclei in the air.

The size of snowflake crystals is closely related to the temperature at which water vapor condenses and crystallizes. The colder the weather, the lower the temperature and the smaller the snowflake crystal. When the weather is very cold, the diameter of snowflake crystals formed is often less than 0.05 mm. Meteorologists have observed that prismatic ice crystals will form when the temperature is between -8℃ and -5℃.

For crops

Snow is beneficial to the growth and development of crops. Snow is a kind of material with good heat preservation effect, which can protect plants from frostbite in cold winter. The melting of snow water in the next spring can provide a good water supply for vegetation. The power of nature is definitely not a coincidence. Because of the poor thermal conductivity of snow, covering the soil surface with a layer of snow cover can reduce the diffusion of soil heat and prevent the cold from invading the snow surface. Therefore, crops protected by snow can survive the winter safely.

Snow can also store water for crops. In addition, snow can enhance soil fertility. According to the determination, every 1 liter of snow water contains about 7.5 grams of nitride. Snow water permeates the soil, which is equivalent to applying nitrogen fertilizer once. Feeding livestock and poultry with snow water and irrigating crops can obtain obvious benefits.