Clouds

Clouds are objects background layer in game. They appear on the title screen, and seem to act as a "loading bar" when you are generating or loading a world.

Clouds change color depending on certain events. During the day, clouds are white. At twilight they turn maroon and at night they turn a dull gray color.

Clouds also change color when you enter the corruption biome - a yellow-brown color during day, and blood red at night. The clouds are also blood red during a blood moon.

Apart from being able to tell time and location, clouds have no real function in the game. It is possible, however unlikely, that clouds will have an effect on the item cloud in a bottle in the future.