What type of cloud is typically associated with negligible turbulence?

Cirrostratus clouds are typically associated with negligible turbulence primarily due to their high altitude and the way they form. These clouds are composed of ice crystals and are generally thin and wispy, often covering the sky in a veil-like layer. Because they develop at altitudes above 20,000 feet, the air is generally stable in these regions, contributing to a smooth flight experience for aircraft.

In contrast, other cloud types mentioned can be associated with varying levels of turbulence. Cumulus clouds, especially when they are developing, can produce turbulence due to vertical motion as they grow. Cumulonimbus clouds are known for their strong updrafts and downdrafts, which can create severe turbulence, and Nimbostratus clouds are typically associated with continuous precipitation and can also lead to turbulence in the lower atmosphere. Therefore, cirrostratus clouds stand out as the type of cloud with the least turbulence impact on flight conditions.