Animals and birds are typically quiet except around their breeding season, within family groups, or in defense of their nest or territory. More social animals, like wolves, can often be heard as they use calling to keep in touch and communicate with others in the pack throughout the year. But the peak time to hear wolves howling is still in the breeding season.
The breeding season for coyotes, wolves, and owls is generally in the time frame of January through February, although I have often heard them starting from November. At this time they will vocalize more freely. As far as I know, the breeding season is the same time no mater if you are in the southern or northern states. If you know differently, please leave a comment. At this time, these animals will be very responsive to call broadcasting, and thus, this is the time frame that population censuses are conducted on these animals. Typically, a researcher will broadcast the common call of the bird or animal with loudspeakers, and listens for the number of responses throughout a planned course of travel, calling about every quarter mile or so. You can try to imitate the calls with your own voice and many times get a response. Be aware, that coyotes and wolves may run to you location to fend off a potential intruder in their territory. The best time to hear these animals vocalize naturally is after sunset, since there are nocturnal. I found the most common time to hear them are starting about a half hour after sunset until a few hours after sunset.
The next time, of the year, it is common to hear coyotes, wolves, and owls is when the young start to move about, during the months of May through July for owls, and April through August for coyotes and wolves. At this time, the young accompany the parents to learn hunting. Young owls often screech more than use the typical call for many months.
I should note, that with coyotes, there is a distinct difference between the Western and Eastern states in the way they vocalize. In the Western states it is much more common to hear coyotes throughout the year. Coyotes in the Eastern states are much less vocal. The theory is that the higher density of people, and domestic dogs in the Eastern states have caused the coyotes living there to be less vocal.
Go out and take some walks during the darkness and experience the calls of coyotes, wolves, and owls. It can be spine tingling spooky to hear a pack of coyotes or wolves, but an almost friendly reminder that others roam the darkness. My favorite owl is the Barred Owl, which is known for a vast repertoire of vocalizations from hoots, screams, whistles, and cackles.