曇る（くもる）— become cloudy
空 が 曇ります。
The sky will become cloudy.
曇るくもる
become cloudy
くもる
accent [2]In detail
Words
空sorasky
がga(subject marker)
曇りますkumorimasubecome cloudy (polite)
Kanji
曇ドン・
曇る is a godan verb. 曇ります describes becoming cloudy; 曇り is the related noun used in weather forecasts.
Coco-sensei