Rasbat is correct.
It’s interesting to note too, that in the early monastic days, the hours were fixed not by a clock but by the sun. The prayers were arranged as such:
Vigils in the night
Lauds at sunrise
Prime at the “first hour” of the day, about an hour after sunrise
Terce at the “third hour” about 3 hours after sunrise
Sext at the “sixth hour” etc…
None at the “ninth hour”
Vespers at “the lighting of the lamps” (or sundown)
Compline before Grand Silence.
As you can imagine, the day was longer in summer and shorter in winter. To accommodate the shorter summer nights, the Rule of St. Benedict prescribed shorter readings at Vigils (which has migrated to become today’s Office of Readings in the secular Liturgy of the Hours).
With time these hours became fixed to a clock; and after Vatican II, Prime could be omitted from the Monastic Office and was definitely abolished from the Roman (secular) Liturgy of the Hours.
I’m an oblate of a Benedictine abbey and their schedule is:
Vigils 5 am
Lauds 7:30 am
Terce 9:45 am
Sext+None (weekdays) noon
Sext+None (Sundays and feasts) 3:45 pm
Vespers 5 pm
Compline 7:45 pm
Grand Silence (9 pm until Terce).
I follow more or less the same schedule except for Compline and I pray None separately (unless I have to be out for the afternoon) at 3 pm.
If you go on various monastery web sites, you’ll find as many schedules as there are monasteries; each has the authority to fix its own schedule. The only requirement is that the verity of the hour be respected. In practice, that means that Lauds, for instance, is a morning prayer that can be said at any time from about sunrise until roughly 8:30 am, and Vespers from 4 pm to 8 pm; it wouldn’t do, for example, to celebrate Lauds at mid-day. Most monasteries do ensure that monks get a full 8 hours sleep so they also tend to go to bed very early. Some will have interrupted sleep, or allow for a siesta after lunch (the Rule of St. Benedict allows for a siesta mid-day). The Carthusians tend to be the most rigorous with their schedule although they don’t meet in choir for all hours; Vigils is however always in community, some hours are always said alone in the private oratory of their cells.