There are several reasons for that. Late summer is a period when pups are nearly full grown. Furthermore, packs are breaking up and the young are starting to venture out on their own, away from the watchful guidance of their parents for the first time. Like naive teenagers, they’re very curious and foolhardy. Also, adults haven’t been bothered for a while.
This makes them very susceptible to calling. Typical prey distress calls, which can be used year round, work fine. This is also a good time for social calls like howls, pups in distress or simple greeting calls, all of which can be imitated with mouth calls, or come with the better electronic callers.
In some cases you may not even need calls. In agricultural areas for instance, it’s haying or harvest season. Coyotes will be out hunting the recently cut fields for prey, and so should you.
Weather, particularly temperature, can often be a factor. It’s much more pleasant to be out and about on a balmy August afternoon than a dreary December day. However, the balmy temperatures also mean sweat, and the accompanying odor, and bugs.
Proper scent control is critical. Wash your clothing and yourself in some kind of scent free soaps, like Sport-Wash. Then remember to spray your clothing and equipment down with an odor reducing solution like N-O-DOR, particularly if you are riding between calling locations on an ATV.
Some type of insect repellant is also called for both for comfort and to minimize movement. The best option here is something called a ThermaCELL, which will repel most biting insects with a scent that won’t repel predators.
Other than that, it’s pretty much standard operating procedures as far as hunting tactics, which can vary with terrain, topography, habitat and other local conditions. Sit still, use good camo and shoot straight.