Dixon is right about the wind. A constant 15-20 mph wind will blow up 6-8' on the outer reef off Islamorada through Long Key because it's 8 miles offshore.
I briefly lived in Layton (Long Key) back in the mid 70's, and remember the frustration of springtime high winds and big seas when I wanted to fish for big grouper or billfish over the deep reef (200' - 300'+) reef south of Tavernier. And I had a 25' Mako with twin 105's back then.
But the problem with June is you can't take any bugs while diving, and late May is the start of the no-see-um feeding frenzy which lasts through early October
Just got back from 9 days at Bahia Honda, just west of Marathon. (We go every year for Thanksgiving) Weather was the best in 10 years. 8-10 mph wind every day, highs in the mid 70's, lows in the low 60's.
Limited out on snapper twice. Hooked and played a while with the biggest lemon shark I have ever seen before finally cutting him off. She towed my little 12' aluminum utility v-hull pretty fast

She seemed to be bigger than my boat when she followed my bait to the boat, but I guess she was really 9'-10'. I had never before seen one over about 7'.
I vote for the Keys, but timing is an issue for us.
__________________
Common Sense is learning from your mistakes. Wisdom is learning from the other guy's mistakes.
Fr. Frank says:
Jesus liked fishing, too. He even walked on water to get to the boat!
Currently without a SeaCraft 
(2) Pompano 12' fishing kayaks
'73 Cobia 18' prototype "Casting Skiff", 70hp Mercury