How to say "day-to-day" in Japanese

• その日その日そのひそのひ
  expressionCovers 'from day to day': each day taken as it comes, often coping one day at a time rather than planning ahead. It is not the word for labeling work or life as routine.
  その日ひその日ひで天気てんきは変かわる。↗

  The weather varies from day to day.
• 日常的にちじょうてき
  na-adjectiveCovers the 'routine, everyday' sense: use it to describe work, chores, or events as an ordinary, unremarkable part of daily life, when 'day-to-day' means habitual rather than day-by-day.

For 'day-to-day', 「その日その日」 handles the 'from day to day' sense of taking each day as it comes, while 日常的 describes things as routine, everyday, or unremarkable; both are relatively uncommon choices.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• その日その日そのひそのひeach day
• 日常的にちじょうてきmundane