Here's why:

* Appearance: Stratus clouds are known for their flat, sheet-like appearance, often covering the entire sky like a grey blanket.

* Color: They typically have a dull gray color, sometimes appearing almost white if they are thin.

* Precipitation: Stratus clouds can bring light rain, drizzle, or snow.

Other possibilities:

* Nimbostratus clouds: These are a darker, thicker version of stratus clouds that usually produce heavier rain or snow.

* Altostratus clouds: These are higher-altitude clouds that can also appear sheet-like, but they often have a more fibrous texture.

If you can provide more details about the cloud's appearance, such as their thickness, texture, or altitude, I can help you identify them more accurately.