Summer is usally a kid's default favorite season, probably because they're out of school. They couldn't care less about any of the other things that summer might mean.
So we leave childhood still feeling like summer should be our favorite time. For a lot of people, it is.
The past couple years have taught me I like all the other seasons more. Summer means:
So when the fall and winter come, things calm down, the bugs disappear for months, you can let nice breezes cool your house, etc. Less nuisances basically.