After an autumn rain on Thursday, an unusual scene of advection fog appeared over Yuncheng city in north China's Shanxi Province. 

Advection fog is formed when warm and moist air move horizontally over to a cooler ground surface and cooled down to appear as fog. Wind and temperature difference are two important factors to form such a scene.

It is rare to see the advection fog in the city because it usually takes place on or nearby a river or sea.

(All images via VCG)

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