You've picked the height of the hurricane season. November will be better than
either September or October. IFR flying in the Bahamas tends to be a local
event, except at night, then it's everywhere (by law).

I just found data that confirms November as being better mainly from a
lightning strike (thinderstorm) point of view


http://www.srh.noaa.gov/tbw/information/ltg/ltg2.gif

http://www.srh.noaa.gov/tbw/information/ltg/ltg3.gif

If I interpret them correct, some part of October is a factor of ten
better than even September (Less thunderstorm activity). Then
November and December are better still.

Ron Lee