The Dies Irae persists as an optional hymn for the Liturgy of the Hours during this last week of Ordinary Time. If you look in your breviary this time of year, you will find it broken up for the various hours. In the typical edition it appears at the beginning of the proper for the week, starting on page 489. If you have the Catholic Book Publishing Company American English LoH, it's in an appendix, starting on page 2013.
But here's my question. I know this will be a surprise, but I can't find the rubric that permits the Dies Irae this week. Perhaps that's all it is, the note at the beginning of the proper for the week in the typical edition, conveniently omitted in the English version. Does this option appear anywhere else?