The main Mediterranean cruise season lasts from April through October. Some ships sail the region year-round, but fewer itineraries are offered in the winter and early spring. Most trips are between seven and 14 days in length and call at ports in a variety of countries.
As temperatures spike in the region during the summer months, tourist traffic also increases. Visitors can avoid some of the heat and crowds by traveling during the shoulder seasons in the spring (April and May) or fall (September and October). The temperatures are still comfortable during these months -- the high temperature in Cairo stays well above 80 degrees for the period and in Rome it's above 65 degrees -- but the number of people visiting the sites and packing the beaches will be greatly reduced.
Visitors who don't mind a bit of a chill might enjoy an off-season cruise during the winter months. Temperatures in the Mediterranean rarely drop below freezing, so it's still a welcome alternative to frigid temperatures and snow.