Our first cruise to Bermuda was in 2010. Second week of September. Humidity and temperature were oppressive. Next year, 2011, went a little later, last week of September to a few days in October. Still too much on the warm side. So then started going last week of October or first week of November. Weather is almost perfect, so much more enjoyable.And hurricane season is over!
Obviously, you can't predict future weather on past statistics. But when historically Bermuda runs about 85 degrees in September, I would take that to mean there is a very good chance that you will have hot and humid weather!
So now NCL ( We only cruise NCL from Boston. Less than an hours drive, and no flying!) has curtailed fall cruises to Bermuda from Beantown, in favor of more (evidently) profitable cruises to Northern New England/ Canada. Our only choice now, to beat the weather, is to cruise in April or early May.