钩卷云（英语：Cirrus uncinus）是其中一种卷云，名字来原于拉丁语的意思蜷曲的钩。 又称海尾mares' tails的钩卷云，通常是簿、稀疏地在海拔七千米天空的对流层出现。

通常界乎摄氏四十至五十度的气温时，钩卷云会在一股暖锋或锢囚锋接近时出现；并意味着雨带和大风天气的来临。

Cirrus uncinus is a type of cirrus cloud. The name cirrus uncinus is derived from Latin, meaning "curly hooks". Also known as mares' tails, these clouds are generally sparse in the sky and very thin.

The clouds occur at very high altitudes, at a temperature of about −50 to −40 °C (−58 to −40 °F). They are generally seen when a warm or occluded front is approaching. They are very high in the troposphere and generally mean that precipitation, usually rain, is approaching.