Squirrel season has been open in Missouri since Memorial Day weekend but the high humidity and 90+ temps aren't conducive to fun hunting.
The first month is my favorite time here in Mo. Get out and hunt until 9 or 10 in the morn. Find a Mulberry tree and sit down about 25 yards away.
You aren't killing young squirrels if you have to wait all summer. I like them lil uns that have twice as much tail as they do body.
That is what a young good tasting squirrel is, about 6 weeks, 2 months old at max.