Fashion seasons - Spring and Fall vs. Summer and Winter

[Pink Jazz]

Based on my experience, with IZOD, usually does complete revamps of their lineups occur with their Spring and Fall lines, while the Summer and Winter lines are usually extensions of the former two, respectively. Typically the Spring lineup is my favorite, and anyone can take a wild guess why.

I was wondering, is this typical within the fashion industry? I wonder why not introduce entirely separate collections with all four seasons?  Is there any particular reason why the big revamps occur with the Spring and Fall collections and not the Summer and Winter collections?

And yes corco, I know I posted this on other forums.

[corco]

http://www.city-data.com/forum/fashion-beauty/2670274-understanding-seasonal-fashion-lineup-refreshes.html

http://www.airliners.net/forum/viewtopic.php?t=1346761