Karen, we were in the Western Med at the end of September one year and it was hot--especially in Italy. Barcelona and Monte Carlo were just pleasantly warm--t-shirt weather. Another year we were again in Italy and further east (Athens, Kusadasi) in October and it was still really warm--but that year we had rain a few days so it was a little cooler those days (like long-sleeve T-shirt weather). I'd say, pack for warm weather, but have a sweater or sweatshirt for evenings/contingencies and raingear in case you hit a storm.