High Season: May to September
Quirks & Perks of Sailing in Season: Both European and American families flock to many of the summer sailing dates (especially in August), making for a nice cultural mix of passengers and plenty of onboard, kid-friendly activities. The tradeoffs are bigger crowds, higher prices (both cruises and airfares) and steamy temperatures that may sap your sightseeing energy. You may find restaurants and other establishments closed in August, which is when much of Europe goes on holiday. September is an increasingly popular time to cruise the Western Mediterranean because you can avoid the school kids and still enjoy warm temperatures.
Low/Shoulder Season: October through April
Quirks & Perks of Sailing in the Off Season: Early-spring and late-fall sailings offer the advantage of more competitive fares and fewer crowds in port. Plus, the weather is often mild (though March and November can be rainy). A very few ships actually remain in the region year-round; look for lower fares and cruises to the warmer regions of the Mediterranean, such as Spain, Morocco and the Canary Islands.