Why is the difference between cloudy day and night smaller than sunny day?

The first one is right, indicating that the temperature difference is small; The temperature is not high on cloudy days, but it is sunny at night, so the temperature difference is small;

On a sunny day, there is less cloud cover, less solar radiation reflection and more solar radiation reaching the surface, so the surface absorbs heat quickly and the temperature is high. At night, due to less cloud cover and weak reverse radiation, the heat preservation effect of the atmosphere is not obvious. Then, because the specific heat capacity is small, the ground temperature drops quickly and the temperature is low at night, the temperature difference is large during the day and small at night, so the temperature difference is large ~