Minor wind swells associated with passing cool fronts are possible, but the Treasure Coast is in luck—unlike strong groundswells, these winds usually only affect surface conditions and rarely change visibility on the bottom.
No doubt freshwater has a big negative impact on the Intracoastal Waterway and the Indian River Lagoon, but It is important to remember these releases do not affect reefs miles offshore since the prevailing north current does a good job of flushing these plumes of brown water away. Dive sites away from local inlets, like the Bethel Shoal area of Fort Pierce or Six Mile Reef and Loran Tower Ledge off of Stuart, are far enough away from shore that the effects are minimal, if any, from freshwater releases.
As fall progresses and temperatures drop offshore, large fish should return to area waters. Spearfishermen will notice the return of large gag and black grouper to area reefs and wrecks when water temperature hits the mid to low 70s. Cooler water may slow fish making them easier to spear but the same effect has been noticed on divers too!
Underprepared divers might consider adding the following equipment for cool-weather diving. Beneath the surface, 5mm wetsuits, hooded vests and neoprene gloves help from becoming cold in the first place. On the surface, basics like dry clothes, a beanie hat and a knee-length dive parka (a ‘boat-coat’) helps to block the wind and warm chilled divers.