Stratus clouds are low, gray clouds that often cover the entire sky like a blanket. They typically form in stable air conditions and can bring light rain or drizzle. Stratus clouds are usually found at altitudes below 2,000 meters (6,500 feet) and can create overcast skies, reducing sunlight. These clouds are part of the cloud classification system, which categorizes clouds based on their appearance and altitude. Stratus clouds can sometimes lead to fog when they are close to the ground, making visibility poor. They are different from other cloud types, such as cumulus or cirrus, which have distinct shapes and heights.