Although I'm not sure it's a conscious decision, when I sat down to write all of my books the weather, or season, has played a huge roll in the story and when it takes place.
Forget the fact that with YA you have the school year to contend with, so if you're writing a story that plays off of things that occur at school, etc. it's sort of important to make sure your book actually takes place when school is in session. That's sort of a no-brainer. I think it's more a matter of how weather impacts characters and what they can do and their state of mind.
One of my next books starts right around Thanksgiving, just as the weather is getting cold. As the story progresses, it gets cold, it snows, and it has a sort of chilling effect on the main character and what's going on around her. Two things happen when it gets cold, you can either draw into yourself and isolate yourself, or you can seek warmth and comfort from others. Winter can either be cozy or it can be lonely. And in the book it is a little of both.
Then there's the sequel to The Book of Luke, which I am finishing up as well. Unlike the first book, which takes place during school, and which had school, and its social dynamics, as a large part of the story, the sequel takes place after graduation. Totally different feel. It's summer, the characters are less inhibited, there are fewer rules, etc. It not only changes individual characters, but the dynamics between characters. At the end of the book, as summer ends and Fall arrives, things change once again - some endings and along with them new beginnings.
I've written two books that take place during the summer (Local Girls and Rich Boys). And they were so much fun to write, anything can happen. And I've written two books that take place during the school year (Plan B and The Book of Luke). They had a structure and sort of "confines" to them that had to be worked within.
So, while weather obviously impacts what takes place in a story, it also impacts how you think about writing the story and the characters that play within that story. And, I have to admit, it's a lot easier to write a summer book when it's not single digits outside and snowing!