1. Aroma = volatile.
2. Extraction = increasing at higher tempertures, however, you run the risk off off flavors from the yeast and volatilization of the aroma through the air lock.
Either cold crash dry hop for a longer amount of time, resulting in a cleaner yeast profile, and great aroma or dry hop at fermentation temperatures, and possibly lose this aroma, as well as subject the aroma to volitalization.
For a quick fix, room temperature or ferm temperture is fine, however, if I'm not in a rush, I'll let the dry hop sit in secondary cold crash. Result = Clear beer, good aroma, minimal off flavors.