Day after day; every day. Indicates something occurring on consecutive days.
連日ニュースでその事件が報道されている。
The incident has been reported in the news day after day.
彼は連日残業が続いている。
He has been working overtime day after day.
連日猛暑が続き、外出を控えた。
The heat continued day after day, so I avoided going out.