We love to go in September and October and rarely have had a day ruined fully by weather. Often it's a mix. Dingle is fantastic and well worth 2-3 days. There is plenty to do that time of year. Sadly the trips out to the Blaskets will be pretty much done then but there might be a slim chance that late in October you might be able to get a ride out there. If you get a beautiful day it is totally worth it. I'd contact the Dingle Visitors Center and ask for Billy 's boat service.....he owns property out on the blaskets, gives spectacular tours and goes out there often.....he might be going or know who would if anyone is. Great guy !
Don't worry it's a great place rain or shine. One of our favorite Slea Head days was slashing rain with wind gusts up to 40-50 mph. We were virtually alone and the seas were insane......So beautiful. Even on that very stormy day the scenery was haunting and spectacular. Have a GREAT time and follow that excellent advice on the convivial pub !