yeah i guess on a weekend its the best, maybe on a friday evening. If some people wants to go out one night in weekend, i guess they prefer saturday than friday.
But also all people from America with -6 gmt would prefer a saturday i guess, so it would be around 16:00 for them and some probably work friday at 16:00.
So i'd say the best to get the most people is a friday in august, 8pm gmt