The book of Hosea is full of references to “days”. These are not twenty-four hour periods, but eras of varying duration notable for specific features.
In chapter 1, Hosea prophesies of a day then future and now past, when Israel’s strength would be broken in the valley of Jezreel and its people dispersed among the nations, and another, much more distant day in which Israel and Judah will finally be reunited. In chapter 2 there are the “days of the Baals”, the “days of Israel’s youth”, and the “day” when the nation came out of Egypt.
Then there are three references in the last few verses of chapter 2 to a coming era of restoration, peace, safety and blessing, characterized by righteousness, justice, love and mercy. Our English translators consistently label it “that day”, though the language used about it strongly suggests this day will be at least 1,000 years in duration. Needless to say, the events which set it apart from all other days in Israel’s history have yet to take place.