Why do i catch so many blue crabs in august?

during the late spring and early summer crabbing picks up but for my area,(just south of baltimore) it seems crabbing hits peak around august you can seem them everywhere!! from the shore line rocks to the beachs even on the sides of piers my question is why? why does it pick up during august but its hard to catch more then a few dozen in july sure im in shallow water just about 5ft sometimes 8 so shallowish water for crabbing but that doesnt seem to matter in august