비 많이 와요.
Bi ma-ni wa-yo
Rain comes a lot.
Simple
비가 엄청 많이 오고 있어요, 나가지 마세요.
Bi-ga eom-cheong ma-ni o-go i-sseo-yo, na-ga-ji ma-se-yo
Rain is coming enormously, don't go out.
엄청 = enormously, very common Korean intensifier
비가 억수같이 쏟아지는데 우산도 소용없겠다!
Bi-ga eok-su-ga-chi sso-da-ji-neun-de u-san-do so-yong-eop-get-da!
Rain pouring like a torrent, even an umbrella would be useless!
억수같이 = like a torrent, 소용없다 = useless/pointless
More Korean Weather Phrases