A cloudy day refers to a weather condition where clouds cover most or all of the sky, blocking out direct sunlight. Clouds are formed by water droplets or ice crystals suspended in the atmosphere and can vary greatly in thickness, appearance, and altitude. A cloudy day is often associated with overcast skies, which means that the clouds are at a low altitude and cover most of the sky. This type of weather can create a gloomy mood or feeling, as sunlight is limited and visibility may be reduced due to the clouds blocking out direct light.