Dubrovnik to JFK. Is there enough time to make connecting flight

The first question to be asked. Is it one ticket or two? Different answers depending on ticket arrangement. If one ticket probably OK. Two tickets and it is too much risk especially late in the day.

My husband and I were on a similar Delta/KLM flight last September. (Depart Dubrovnik at 1:25pm and Arrive Amsterdam at 3:50pm; Departing for JFK at 5:05pm) We did make our flight! It was a bit touch and go but think we really were in no danger of missing our flight. There were a number of passengers on the Dubrovnik flight taking the flight to JFK. When we exited the Dubrovnik flight, there was no signage and no one to tell you which way to go. Everyone getting off the flight was confused and worried about the limited time to make the connection. After a few minutes, we made a choice and walked one way, eventually coming to plenty of signage. At some point, the airport had a special line for flights departing soon. These flight numbers were clearly marked and there were helpful airport personnel to get you going in the right direction. I would say when we arrived at the gate, we were near the end of boarding but in good company with others boarding from our flight too. FYI - We are in our early 70s and had our suitcases with us. All that being said, we would have preferred to have a bit more time to connect. A major problem would be if the Dubrovnik flight arrived late.

That sounds good to me — leaving Dubrovnik at a civilized hour rather than a very early morning flight, and the Dubrovnik airport is about 40 minutes from the city. You’ll very likely make it, and worst that could happen (assuming you’re on one ticket) is that KLM puts you up for the night and you fly to JFK the next day.