Yes! It's summer. It's hot and promises to get hotter. Imagine yourself sitting in the woods without a breath of air moving. You're in your full body jute ghillie suit and are trying hard not to move. As you sit a lot of things go through your mind. You follow with your mind that little bead of sweat that just formed on your back and like all it's predecessors, trickled right into your butt-crack. You wonder why you just had to have a jute suit instead of the lightweight synthetics. You wish you had sprung for the hydration pack. Will they ever build a ghillie suit with built-in air-conditioning? Now that they are abandoning the space program, maybe you can get one of NASA's air-conditioned space suits (in a camo pattern) on sale at your local army surplus store.
Take heart! While you are out enjoying yourself, your loving wife and adorable chidren are enjoying air-conditioned comfort at the mall. Maybe they will think to get you some salt tablets to combat your dehydration.
Maybe the heat and gnats will be easier to endure if you remember little sayings like "this is character-building" or "what doesn't kill you, makes you stronger". It doesn't take a lot of time in a ghillie suit this time of year before you understand why most hunting seasons start in the fall.
Paintballers have the option of wearing a ghillie jacket without the ghillie pants or even a head and shoulders ghillie poncho. A lot of ghillie suits are built on a base of mesh that allows for a little air movement. All the ghillie ponchos I know of are built this way.
I recommend a suit for every season. A head and shoulders poncho for the hot hot summertime. One of the ultralight 4 piece synthetic suits for fall. A BDU ghillie suit for the winter along with a white ghillie poncho when it snows. The autumnal suit can also be used again in the spring. Then you may also want 1 or 2 suits in different color patterns for different terrain.
If you have the money to buy that many ghillie suits, you probably just pay somebody to go out and have fun for you.