I had occasion to go to a city park yesterday evening with my daughter. It wasn't very late, just the hour or two before sunset. An unusual time for me to go, typically I take her in the early afternoon before lunch and this was the latest I'd had her out.
I was struck by what a difference it makes in the composition of people, their activities, and the atmosphere between daytime and evening.
First it was a much more diverse crowd ethnically, economically, and in age. Many more tattoos visible, more people speaking spanish (very few in day time), more parent couples rather then individuals. Also many more young adults using the park for sports and recreation, in daytime it's pretty exclusively the domain of parents (or au pairs) with kids, and the homeless.
The biggest difference was atmosphere- much more energetic and fun. People were relaxed and eager to talk with each other, eager to improvise and blow off steam. The daytime crowd in contrast is reserved, the parents intently monitoring their children's activity.
I think the fundamental driver was that the evening crowd was people coming out after work rather then housewives (or husbands) killing time. The evening crowd was playing, very conscious of not being under the restrictions that govern work whereas the daytime crowd for the most part was AT work, taking care of their kids.
An unexpected experience.