Legba- Coyotes are fair game all year around here in AZ but most take denning months off and the summer months, June through August, are so hot few go out at sun up and sundown to get in the 45 minutes that are in the 90's. Coyotes are few and far between when it's 115 degrees outside.
Like Jimanaz, I have found the Rancho Safari ghillie suits to be great in masking movement plus an all around fantastic camouflage tool. I have found I can turn my head from side to side within the hood and there is very slight, if any movement. The downside of the suit is it is pretty warm. Even now as the sun gets around 11 o'clock and its 60-65 degrees outside, the suit gets pretty hot. I end up shedding it for my Advantage Max 1 3d camos.
I have found that as much of a factor as the pattern of camo you are using is your movement while on stand. I have hunted with tons of people who all wear different camo and they all call in coyotes.
I tend to want to get the coyotes in as close as I can so I wear what I wear. Does it work? Yes, I'm at 22 coyotes, a fox and 2 bobcats since the end of September. I bet I have called in triple that but failed to knock them down for one reason or another.