风切变，又称风切或风剪，是指大气中不同两点之间的风速或风向的剧烈变化。

根据两点高度之间的差异，风切变可分为水平和垂直两大类。

垂直风切变

是指垂直于地表方向上风速或风向随高度的剧烈变化，强烈的垂直风切变的存在会对桥梁、高层建筑、航空飞行等造成强烈的破坏作用，可造成桥梁楼房坍塌、飞机坠毁等恶性事故，给人类生活造成严重影响。

水平风切变

则指与地面平行的方向上风向的急速转变。

Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with change in altitude. Horizontal wind shear is a change in wind speed with change in lateral position for a given altitude.