expression
on every occasion; at all times; both ordinary and special times
A set phrase meaning 'whether it's an ordinary day or a special day'—i.e., always, on any occasion. Often used in literary or formal contexts.
彼女は褻にも晴れにも美しい装いを心がけている。
She always dresses beautifully, whether it's an ordinary day or a special occasion.
この店は褻にも晴れにも使える品揃えが魅力だ。
The appeal of this shop is its selection of items that can be used on any occasion.