This question was answered on our Cruise IQ show on August 17, 2017.
Most cruise lines offer Mediterranean cruises May through October each year, and some offer year-round programs. Summer months are the peak for travel to Europe and with the increase in people and possible crowding in some of the smaller European ports you can visit, the cost in the summer is typically much higher. Since many of the cruise ships sailing in the Mediterranean are there seasonally, you will typically find the best prices at the beginning and end of the season. Booking a cruise for early May or late October, may allow you to get a lower price and perhaps upgrade to a higher room category. If you want to cruise in the Summer months, July typically has the highest prices and to get your preferred room choice, you’ll want to book as early as possible. Another difference in cruising the Mediterranean in the peak of summer versus early or later in the season is the weather. In the spring or fall, the temperatures are warm and comfortable, while in July & August you can expect it to be hot and scorching, which is great if you plan to hit the beaches, but not so great for site seeing.