My daughter had dreadful weather going from Southampton to New York in October a few years ago - sick all the time. But your more southerly route should be bette.
Depends on which route she takes. If you cruise is going on a more southerly route then you will probably be in luck and get a fair amount of sunshine and warm to hot weather. If, on the other hand, you are steaming via say Bermuda and taking a course straight to Lisbon the weather is notoriously fickle and at that time of year you are more likely to have some mist or fog, possible a storm, but you can have fine weather. If the current weather has any bearing then you could come through with some fronts as has happened since May. Look at your route and go on the net closer to the time and look up the weather forecasts to be more accurate. I hope you are going on the more southerly route….Neil Dow.