Rime is a milky white ice crystal deposit formed by direct sublimation of water vapor in the air at low temperatures or direct freezing of supercooled fog droplets on objects. It is a very rare natural wonder.

Rime is neither ice nor snow, but the result of the continuous accumulation of frozen and sticky water vapor below zero degrees Celsius in the fog on branches and other objects with the wind, which appears as white opaque granular structure deposits.

The formation of rime requires a very low temperature and sufficient water vapor. It is even rare to have these two extremely important and contradictory natural conditions for the formation of rime.

Rime is a white or milky white opaque ice layer attached to the windward surface of ground objects. It is also formed by the condensation of supercooled water droplets.

Rime is formed when supercooled water droplets collide with objects that are also below-freezing temperatures. When the water vapor in the air collides with an object and immediately condenses into a solid state, it will form a rime layer or time deposit.

In general winter, the probability of sunny days and calm wind or light wind weather at the same time is not very high. In addition, the growth of ice crystals on ground objects is particularly favorable when there is supercooling fog.

At this time, white ice flowers are formed on the wires and branches, which are called "rime".

When there is fog and the temperature is higher than 0°C, fog droplets attach and gather on leaves or other objects, which is called "fog condensation", which is most common in forests.

The harsh conditions for the formation of rime are first that it requires both a long cold winter and sufficient water vapor in the air. The formation of rime requires both a clear sky and few clouds, and still wind, or the wind speed is very small.

The clouds in the sky are like a quilt for the earth. When there are clouds at night, the outward long-wave radiation is weakened, the temperature on the ground drops slowly, the temperature difference between day and night is relatively small, and the water vapor in the air near the ground will not condense.

There are two types of rime, hard rime and soft rime.

Hard rime, rime, frost, and dew are all formed due to the temperature difference between the air and ground objects.

Soft rime is a white deposit that forms as droplets of water condense on frozen outer surfaces in semi-frozen fog or mist, in calm or light wind conditions.