Three in the afternoon is the end of the federal working day — offices close at 3:30 pm — so this is the last window for anything needing a government counter, a stamp or a ministry phone line before tomorrow.
It is also when the afternoon prayer falls for much of the year, and when outdoor work resumes after the summer midday pause. On a construction site the two markers together define the shape of the second half of the day.
For anyone working with Europe, three o'clock is the point at which the other end is properly awake, which makes it a natural boundary in a calendar: local work before it, international work after. A countdown to 3 pm is usually about catching one or the other, and it resets every day.
Common questions
When do government offices close?
At 3:30 pm on a normal working day, which makes three o'clock the last practical window for anything needing a counter.