na-adjective
bright; clear; fine; beautiful; glorious; splendid; cheerful
Describes pleasant spring weather, a bright mood, or a clear, beautiful voice. Often used in literary or poetic contexts.
今日はうららかな春の日ですね。
It's a bright spring day today, isn't it?
彼女のうららかな声が部屋に響
Her clear, beautiful voice echoed through the room.
The origin is uncertain, but it is a native Japanese word. The kanji 麗 is used for its meaning of 'beautiful' or 'bright'.