Hello suerita, welcome to Cruise-Chat! No one can predict what the weather is going to be, but when I did the crossing on the Navagator in April of 2008 the weather was sunny, an average of 64 degrees, and the seas where around 3 to 5 feet which is pretty smooth for a "Voyager" class ship. We want to do another transatlantic some time.
I've crossed the Atlantic a few times and have had calm seas and sunshine one day and 40 foot waves and cold the next day. It's the weather. Nobody can say what it will be in early May.