It's pretty dependant upon a few factors. Time of day, how the bull is behaving, how many cows I think he has and what sort of terrain/ cover we are in.
Obviously, the wind matters too but my assumption is that if I am there, I feel like the wind is right.
I'm most likely to push in mid- day, with a bull that isn't moving too fast or too much, with fewer cows and in thicker cover.
I hunt Roosevelts.