多云。
Duō yún
Many clouds.
Weather forecast shorthand
今天天空阴沉沉的。
Jīn tiān tiān kōng yīn chén chén de
Today the sky is gloomy.
阴沉沉 = gloomy/dark, reduplication adds emphasis
乌云密布，感觉快下雨了。
Wū yún mì bù, gǎn juě kuài xià yǔ le
Dark clouds densely covering, feels like rain is coming.
乌云密布 = classic idiom for ominous clouds
More Chinese (Mandarin) Weather Phrases