Temp and humidity are a factor yes... But I think the manufacturer has more to do with drying time. (I use dupli color for the smooth actuator and quick drying times)
What I do is apply a light "tack coat", then wait 5 - 10 minutes, then spray a thicker full coverage coat. This should give you a smooth finish.
Practice of a scrap piece of wood. See what works best with the paint you have.