Purely geography only. I'll break down into points. What I'm giving you below is just to narrow down the possibility, but otherwise, quite arbitrary.
Assuming a large archipelago of islands existed on real Earth at one point in the geologic history.
The combined area of the islands is let, say, half the size of Indonesia (if size has any relevancy at all).
Situated approximately at the center of the North Atlantic Ocean, east of the Bahamas.
Its northernmost point is at the same latitude as Charlotte, North Carolina. Its southernmost point is at the same latitude as Port-au-Prince, Haiti. Its westernmost point is at the same longitude as Port of Spain, Trinidad and Tobago. Its easternmost point is at the same longitude as the easternmost point of Brazil.
The island has elevations and terrains no different than typical islands in the Caribbean.
The largest island is no bigger than Cuba. Most islands are less than 100 km^2, and the archipelago contained thousands of them. The islands are relatively tightly clustered.
So let's get to the question, what would be the possible climate description of this archipelago? Feel free to make assumption about the terrain factors.