Q. If one says slichos at 10pm for no good reason, are they yotzee?
A. See question 1833 above, and the Poskim quoted that prohibit, based on the Zohar and Cabbala, to recite selichos before midnight. However, we quoted other opinions that permit in need. Some add that at least one should recite selichos during the middle ashmora or the second third of the night, which begins approximately two hours before midnight.
Mishmeres Sholom and Igros Moshe (ibid.) recommend to recite when in need, at the time the mishmaros or thirds change. (From the first to the second).
Horav Shlomo Miller’s Shlit’a opinion, as mentioned above is that in need and difficulty of staying late at night, one should better recite in the morning before davening as one does in the rest of the days.
After the fact, if one did recite earlier the Rov follows the opinions that one complies.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a