Nimbus clouds are usually found low in the sky, typically below 2,000 meters (6,500 feet). They are associated with rain, snow, or other forms of precipitation.

Here's a breakdown:

* Nimbostratus (Ns): These are dark, gray, layered clouds that cover the entire sky. They often produce steady, long-lasting precipitation.

* Cumulonimbus (Cb): These are towering clouds that can extend up to 12 km (39,000 feet) or more. They are associated with thunderstorms, heavy rain, hail, and even tornadoes.

While nimbus clouds are typically low, Cumulonimbus clouds can extend through the entire troposphere and even into the lower stratosphere.

It's important to note that the specific altitude of nimbus clouds can vary depending on geographic location and weather conditions.