Here's why:
* Clouds reflect sunlight back into space: Clouds act like a giant mirror, reflecting a significant portion of incoming solar radiation back into space. This means less sunlight reaches the Earth's surface.
* Clouds absorb some sunlight: Clouds also absorb some sunlight, converting it into heat. This heat is then released back into the atmosphere, warming the air but not directly reaching the surface.
* Clear skies allow maximum absorption: When the sky is clear, there is little to no reflection or absorption of sunlight, allowing the maximum amount of solar energy to reach the Earth's surface.
Other factors also play a role, but to a lesser extent:
* Latitude: Areas closer to the equator receive more direct sunlight and therefore more solar energy.
* Season: The angle of the sun in the sky changes throughout the year, affecting the amount of sunlight that reaches the Earth's surface.
* Surface characteristics: Dark surfaces like asphalt absorb more solar energy than light surfaces like snow.
* Atmospheric composition: Gases like water vapor and carbon dioxide can absorb some of the incoming solar radiation.
However, cloud cover is the dominant factor because it directly affects the amount of sunlight that actually reaches the Earth's surface.
