I think it is nimbostatus but don't quote me on it.
a grey one
When you see a precipitation cloud (Nimbostratus or Cumulonimbus) you can never tell if it will be rain or snow until the snow actually begins
Cirrostratus Clouds
Cirrus
Nimbo-Stratus
No. The atoms themselves do not change.
Nimbostratus clouds are thick enough to blot out sunlight. This type of cloud is associated with heavy, continuous rain or snow.
precipitation
it snows in winter months because the water in the clouds freeze and the cloud cant hold it for long because it gets heavy ,so then the snow falls and that's that.
When water becomes too heavy to remain in the air as a cloud, it precipitates. This can be in the form of rain, snow, or hail.
Cumulus sunny day Stratus rain and cirrus light rain or snow is coming
If by nimbus you mean nimbostratus, they produce light to moderate rain or snow over a long time. If you mean cumulonimbus, they produce showers of heavy rain. Cumulonimbus also can produce hail, snow, lightning, strong wind and tornadoes. These clouds are also associated with hurricanes, but generally, they are the thunderstorm cloud.