conditions question

I'm due to show up in Key Largo the 29th and be in the area a couple weeks, and I was just looking at the marine forecast down there. Looks like for the next week or so the swells will be running around "4-6 ft outside the reef and 2-3 ft inside the reef".
And I'm wondering what is the typical cut off point there?
I've dove in a few different places and they all seem to be different. California had me out there in 6 ft swells, Jamaica shut down when he breeze made a ripple. I know there are variables, such as the size of the boat, but what is the median shut down point?
And does rainfall have an effect on visibility?
Thanks, ya'll have a nice evening, goin out.

Depends on the dive shop. One shop I use a lot will shut down if there are less than three divers (some divers chicken out when the wind's up) and are really conservative about wave action. Others don't really worry too much about it unless it is a gale. I've changed shops several times when one wouldn't go out and when we got out there it was only a one or two foot chop. I've dove the Speigle Grove in four to five footers with one shop while another wouldn't even fuel up their boat. Main thing is to contact several operators in advance, preferably days before, and get an idea of how they will be operating. If the weather is maginal I'll telephone and/or stop and talk with them on my drive down while passing through Largo and Tavernier, going to Islamorada where I stay, and see what's up.------I've dove in some pretty hard rains and haven't noticed any effect on vis from it. I think that visibility has to do with where the Gulf Stream is at the moment, current direction, and from which direction the wind has been blowing. You're gonna like diving off of Largo. Best diving in the USA.

Garrabo, thanks! And yes I dove Key Largo before, and I agree. The best diving in the states. But the weather just happened to be perfect, blue skies, calm seas, so the question of what their dive call limits are wasn't an issue. But it looks like this time it might be an issue. I has a dive called in Cozumel once, and it wasn't up to individual dive boats to make the call. Down there, it seemed that the authorities made the decision. No dive boats went out at all, no matter how big.
So far I haven't booked anybody, but I've made a list of operators to call in Largo. I'm planning on staying three days in Key Largo, and another three days in Marathon, then who knows.
Not that bigga deal if I don't get to dive really, but it would be nice. There's always the margaritas.
I'll just be glad to get away from all this global warming I have to shovel out of my driveway for a few days.