Looks like SoFL has one event at the end of the month (reg. fees going to MADD) and NOTHING for the rest of the summer, which I suppose can be blamed on the heat, but that seems like more of a rationalization than a proper excuse.
I'm in Lake Worth. I see a lot of riders around early Saturday mornings, but I'm one of those weekday morning clowns you mentioned. I know of one organized riding group associated with the Bicyclery shop attached to Army/Navy/Outdoors south of Okeechobee. I think their Saturday ride departs from lake worth or boynton beach. There's also a sort of ad-hoc group that used to meet up in Wellington, too. don't know if that's still going on.
My impression of riding in PBG is that most cyclists either go it alone or with their SO, not so much in larger groups.