Does hair grow faster in the summer? Why?

I had a haircut earlier this week and the girl who cut my hair told me that hair grows faster in the summer. I’m a bit of a geek, so I started peppering her with questions about why this could be? She had no idea, and just said it was something they taught in beauty school.

Google hasn’t been very helpful for me, so I thought I’d see if anyone here knows why or has a theory. Is this something you’ve heard before?