下雨了。
Xià yǔ le
Rain fell.
了 marks the rain starting
外面在下雨，记得带伞。
Wài miàn zài xià yǔ, jì de dài sǎn
Outside is raining, remember to bring umbrella.
Natural practical sentence
外面下得跟倾盆大雨一样，出不了门！
Wài miàn xià de gēn qīng pén dà yǔ yī yàng, chū bù liǎo mén!
Outside raining like a basin pouring, can't go out!
倾盆大雨 = torrential rain idiom; 出不了门 = can't leave the house
More Chinese (Mandarin) Weather Phrases