There is one real difference between September and October Med cruises - fewer crowds. You will enjoy your port days, and prices in port, much better in October. Yes, weather can get a little iffy but my two mid cruises have been in October and November and never a real weather problem.
"The test of a first rate intelligence is the ability to hold two opposed ideas in the mind at the same time and still retain the ability to function."
F Scott Fitzgerald
Silversea Silver Explorer (23nts) - Kangerlussuaq, Greenland - Nome, Alaska - Aug 14
Seven Seas Voyager (30nts) - Dubai - Cape Town - Nov 14