I've called during the summer months. But only for nuisance Coyotes causing livestock damage.
Prey sounds & Coyote sounds work all year long.
Around July 4th, I've weigh pups in the 15lb. range, in my area.
Locating den sites will aid in your success. For the most part, Coyotes don't move much or far during summer. Once you have 'em peg, make a plan of attack.
Be ready for the whole litter to show during the summer. It happens once in awhile if within earshot..
After your first hunt there, a kill/double/triple kill or a miss, Coyotes may relocate to different den site.
Main thing is fine the Coyotes. Don't listen to your what you neighbor told you about his friend's, brother-in-law's, grandpa's farm.
Do your scouting, do your homework. Fine the Coyotes before you turn on that new call.