Why no 7 day cruises in the summer?

[cyberbox2]

My family and I just took our first Disney Cruise on May27th. It was an unforgettable experience and even though we had 11 more days to spend in Orlando, while leaving the ship it truly felt like our vacation was over

Needless to say we want to take another cruise next summer and would like to extent the magic to a 7day cruise. When I look at the available 7 day cruises on the disneycruiseline.com website, their aren't any 7 day cruises in the summer months, why is this?

 

[makelab]

they are cruising out of california (LA) next summer, so they classify those cruises as 'special mexican riviera' itineraries.