Re: When to Cross the Atlantic
We crossed from St. John's NFLD-Ireland last year. We went at the end of July. Generally, winds are favorable, but you can get some easterlies associated with a low pressure system.
You definitely want to keep an eye on the tropics while making this trip. We made the stop in St. John's specifically to wait for a favorable departure window, and to make sure there wasn't an early tropical storm looking to recurve and turn into a nasty blow on its way back east.
Anyway, as long as the ice zone allows, I would recommend St. John's as a good departure point. Plus, it's a great town for a visit. Bring fenders, though!
TJ, Jenny, and Baxter