If it's raining cats and dogs, why not spend some time at Byzantine Ecclesiastical Museum? You'll be fascinated by just how much you can discover about the past here.
You'll be spoiled for sightseeing choice when visiting Kefalonia. Byzantine Ecclesiastical Museum is a good place to begin here, but there are numerous other worthy spots to appreciate. Lourdas Beach, Trapezaki Beach, and Makris Yalos Beach are not far from the collection of historical artifacts and will round out your day nicely.