Paleokastritsa is lovely to visit at any time but July and August are busier than any other months. In August a number of Italian visitors are in the resort which swells the numbers and in general Paleo is very busy with day trips to the main beach area and the monastry. I enjoy May, June and September as it is hot but not unbearably so and you can lie out, go walking or generally relax without any difficulty and no more than normal precautions against sunburn and dehydration.I have found the temperature to be around 80-90' although it is really building up by the time you get to the end of June.Everything within the resort is open throughout the season but you may find that by the 3rd week in September small supermarkets are not re-filling their shelves. There are larger supermarkets however so you don't go without any of your essential items.The bus service runs from the resort to Corfu Town throughout the season and you will find no change in the amount of buses until the season is coming to an end.