The phrase "when the days are cold" appears to be from the song "Demons" by Imagine Dragons. The lyric starts: "When the days are cold
And the cards all fold
And the saints we see
Are all made of gold..." This is the opening of the song's verse, describing a melancholic and challenging time metaphorically. If the query refers to this lyric or its meaning, it comes from this song released in 2013 by Imagine Dragons.