Here's why:
* Clouds are made of water droplets or ice crystals. These droplets reflect and scatter sunlight in all directions.
* When there are many clouds covering the sky, they block a lot of direct sunlight from reaching the ground. This reduces the amount of blue light that is scattered, resulting in a gray appearance.
* The shade of gray can vary depending on the thickness and type of clouds, as well as the amount of sunlight reaching them.
* Other colors can also be present depending on the time of day and the presence of other atmospheric phenomena. For example, a cloudy sky might have a reddish hue during sunrise or sunset.
So, while the sky can sometimes appear white or even a slightly blueish-gray when clouds are present, the most common color is gray.
