When will the frost and fog appear?

Frost appears in the early morning of cold season.

In the cold season, frost usually forms on sunny, breezy or calm nights.

In the evening or at night, due to radiation cooling, the air layer near the surface also cools down. When the temperature drops below the dew point, that is, the water vapor content in the air is supersaturated, there will be water vapor condensation on the ground or the surface of the object.

If the dew point temperature is below 0℃, water vapor condenses directly on the ground or ground objects into white ice crystals, which is called frost. Sometimes the dew that has been generated freezes into ice beads because the temperature drops below 0℃. This situation is called frozen dew, which actually belongs to the category of frost.

2. Dew

Show up in the morning.

Dew can be formed all year round, and the meteorological conditions for dew formation are sunny and breezy nights.

In the evening or at night, due to radiation cooling, the air layer near the surface also cools down. When the temperature drops below the dew point, that is, the water vapor content in the air is supersaturated, there will be water vapor condensation on the ground or the surface of the object.

If the dew point temperature is above 0℃, tiny water drops will appear on the ground or ground objects, which is called dew.

The meteorological conditions for dew formation are clear and windy nights.

3. Fog

Fog mostly appears between February and April in spring.

Conditions for fog formation: cooling, humidifying and increasing water vapor content.

When the relative humidity reaches 100%, the water vapor in the air will condense into fine water droplets suspended in the air, which will reduce the visibility on the ground. This weather phenomenon is called fog.

Extended data:

Forms of frost, dew and fog

1. Frost is a kind of white ice crystal, which mostly forms at night. In a few cases, it can also begin to form before sunset when the sun is tilted. Usually, the frost will melt soon after sunrise. But when the weather is cold or in a cool place, the frost will last all day.

2. Dew is liquid water, and water vapor in the air condenses on ground objects. Dew can be formed all year round, and its attachments can be grass or other inanimate objects, which can be attached to any part of plants.

3. Fog is liquid, and the duration of fog is mainly related to the humidity of the local climate: generally speaking, the short fog in arid areas dissipates within 1 hour, while the long fog in humid areas is the most common and lasts for about 6 hours.

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