HIS psalm targeted the temple ministers who ministered in the evening. Either there were several work-shifts among the priests, or this psalm was meant to express gratitude to the priests who stayed late to direct, assist and instruct the Jewish pilgrims as they arrived at the temple at various evening hours of the day. Morning worship existed too... as it does today. But, praise God for both ministers and members who come out at night to worship and serve. It really doesn’t matter WHEN we worship, of course, only that we worship, who we worship and how we worship. So, evening praise likely fits some folks’ schedules and/or personalities better than others. God loves early risers and night owls too, you know.
I find it interesting that God said in Hebrews 10:25 that as we see the return of Christ approaching, we should therefore begin to fellowship together in the assembly of the saints more faithfully and we should assemble more often. Yet as Christ's Second Advent approaches, many churches are permanently canceling certain scheduled assemblies. Many members' devotion is declining, and their attendance is decreasing. It doesn't make much sense, but it's true nonetheless. As such, I say with the psalmist, someone praise God in the evening!