Nei giorni feriali mi alzo presto per andare al lavoro.
On weekdays I get up early to go to work.
Ieri era un giorno feriale, perciò il traffico era terribile.
Yesterday was a weekday, so the traffic was terrible.
Il museo sarà aperto anche nei giorni feriali dopo le cinque.
The museum will also be open on weekdays after five.
Note
The article is part of the word: il giorno feriale. That way you learn the gender with it.
Remember il giorno feriale for good. ripiti brings the word back just before you forget it, with these sentences. Free, no account needed, works offline.