Mid-level clouds form between 6,500 feet and 23,000 feet. High-level clouds form above 16,500 feet. Note that there is some general overlap in the heights of mid and high-level clouds.

Nimbostratus Clouds This cloud form appears as foggy-looking layers or sheets in the sky, and it occurs with precipitation (i.e. "nimbo-"). According to Weather.gov, “Resulting from thickening ...