If you understand the clouds are closer to the Sun. Here, the different ability of clouds and the Earth’s surface to reflect and absorb sunlight plays a role. The earth heats up and gives off heat, and clouds often do not have such an opportunity
If we compare the distance from the surface of the Earth to the surface of the Sun and the distance from the cloud level to the surface of the Sun, their ratio will be equal to one with an accuracy of «machine epsilon» — the distance from the Sun does not play any role here.