In the late evening, routine turnout (10)
I believe the answer is:
attendance
'turnout' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for attendance that I've seen before include "Presence; gate" , "Act of being present" , "Number present" , "Number at gathering" , "how many are watching?" .)