Why is the temperature higher when it is cloudy at night than when it is sunny?

Clouds are floating in the air, which are composed of countless small water droplets, small ice crystals or a mixture of the two. Generally, the height varies from 1000 to 5000m. Clouds reflect solar radiation, and the thicker and denser the clouds, the stronger the reflection. When it turns cloudy and cloudy during the day, due to the reflection of solar radiation by clouds, especially the strong reflection of solar radiation by ice crystals, the clouds reflect part of the heat of solar radiation into the universe, which greatly weakens the heat radiated by the sun to the earth. Therefore, when it is cloudy during the day, the temperature near the ground is not as much as that on a sunny day, so the temperature is lower than that on a sunny day.

The influence of clouds on radiation

At night, the earth's surface can't receive solar radiation, so it can't get solar heat directly. Instead, it radiates heat into the air. On a clear and cloudless night, the heat radiated from the ground is fast, and the heat radiated from the atmosphere is very little. The ground can not be compensated by solar radiation heat, which makes the temperature drop rapidly, so the temperature is low. On cloudy nights, dust and water vapor in the clouds can absorb a lot of long-wave radiation from the ground and radiate some heat to the ground in the form of reverse radiation. Moreover, the thicker and lower the cloud, the stronger the reverse radiation, the more compensation for the ground heat, and the smaller the ground temperature drop, so the near-ground temperature is high and the temperature drop is slow. So the temperature is higher on cloudy days than on sunny days at night.