Well, I've traveled throughout the United States and to more foreign countries than I can recall the names of, and from my perspective, from a sailing year round point of view, I would think seriously about the lower Florida Keys, with Marathon right at the top of the list.
Keep in mind that in the mid Atlantic region, particularly in Chesapeake Bay, winter essentially begins in early to mid October and continues through till mid May. Sure, there are exceptions, but those exceptions go in both directions. Last October was one of the coldest I can ever recall, and this spring was extremely cold as well. Warm weather, weather where you you could wear shorts and a short sleeve shirt, really didn't arrive until mid June. Then, as if someone threw a switch, the hottest summer we've experienced in decades was upon us. Today, the temperature in the Chesapeake's upper reaches is 97 degrees, and the humidity is nearly 90 percent. Just like stepping into a sauna.
And, in this part of the world, summer winds average 5 to 10, mainly from the southwest. The only interruption to this is the normal, late afternoon and evening thundershowers, when the winds can suddenly kick up to 50 or more MPH.
Ironically, the weather in Marathon this summer has been about 8 to 12 degrees cooler than it has been here, and the humidity has been about 20 percent lower. Sure, it's hotter longer there, but when you hit retirement age, warmer is a lot better, especially during the 7 months of winter we get here in Maryland and norther neck Virginia.
Now, lets examine the other aspects. The waters of Chesapeake Bay are nothing more than an open sewer. The fish are unfit to eat, as are the shellfish. A few days ago I sailed down the bay just below the confluence of the Elk, Susquehanna and North East rivers, the stench of rotting fish corpses was nearly nauseous, and the water color ranged from dingy brown to greenish gray. There were people wading and swimming near one of the newly created spoils islands just south of Havre de Grace, and for the life of me I really don't know why they would allow themselves or their children be exposed to this kind of health hazard.
In Marathon, there are dozens of edible species of fish, and none with health hazards other than ciguatera, which is extremely rare. The underwater visibility in Boot Key Harbor, which has some pollution issues, ranges from 6 to 15 feet on most days.
As for sailing, on one side of the key is the open waters of the Atlantic, which can quickly be accessed via two inlets, both of which are easy to navigate. On the other side of the key, the Gulf of Mexico offers you some incredible sailing in waters that are relatively shallow, but on average provide depths ranging 6 to 12 feet.
So lets see, Chesapeake Bay or Marathon. Believe me, if it were not for my wife and her family ties, I would have been there 40 years ago.