맑아요.
Mal-ga-yo
It's clear.
Single adjective, easiest
오늘은 맑고 화창해요.
O-neu-reun mal-go hwa-chang-hae-yo
Today is clear and sunny.
화창하다 = bright and sunny, polite form
날씨 죽이네, 이런 날 밖에 있어야지!
Nal-ssi ju-gi-ne, i-reon nal ba-kke i-sseo-ya-ji!
Weather is killer, on a day like this you gotta be outside!
죽이다 = to kill, used as 'awesome/amazing' in slang
More Korean Weather Phrases