A dazzling display of a rainbow cloud filled the sky in southern China.

The impressive video was filmed in the city of Nanning in Guangxi Zhuang Autonomous Region on July 12.

Liang Daiyun, Chief Forecaster at the Nanning Meteorological Bureau, explained that the rainbow cloud is a fairly rare optical spectacle. It occurs when sunlight interacts with the icy structure of the clouds to create this natural phenomenon.

As per Liang, under appropriate weather conditions, the sunlight and clouds form a suitable angle. This, coupled with the effects of refraction and reflection, allows the moisture within the cloud to separate the sunlight into its spectral colours, resulting in the dispersal of a seven-coloured radiance reminiscent of a rainbow cloud.

Liang said the spectacle usually appears on clear, sunny days when the sky is filled with thin, uniform droplet-filled clouds like cirrus or convective clouds.

The video was provided by local media with permission.

7月12日傍晚，广西南宁，天空中出现美丽的七彩祥云，色彩艳丽如彩虹，美不胜收。随着太阳的西降，彩云也在不断变化，整个过程持续了半个多小时。
南宁市气象台首席预报员梁岱云表示，七彩云是一种比较少见的光学现象，是太阳光线通过云彩中的冰晶结构产生的自然现象。从形成原因上说，在合适的天气状况下，太阳光和云构成一个合适的角度，通过折射和反射作用，上空云彩内的水汽将太阳光谱分离，散射出七色光芒，也就变得如彩虹云一般绚丽多彩了。七彩云需要满足一定的条件，一般出现在天气晴朗的白天，云为带有均匀小水滴的薄云，如高积云、卷积云。