I've never understood the practice of designating a vehicle "model year XXXX" when it wasn't built in that year. The changeover date should be Jan 1.
I understand the rationale: a car built in December won't arrive at a dealership until January, but will be "one year older" than a car built just a few days later. But if we can ignore reality when inconvenient, why bother with the pretense at all? Why not just make them all "2035 models"? Woo hoo, it'll still be brand-new when I trade it in!
I used to work for a Tier 1 supplier to the big 3 automakers. The rationale was that they all did the model year change over in the summer for the line workers to take a vacation during that time (obviously the people re-tooling the line didn't get time off). It also gave the Tier 1,2 and 3 suppliers a break and many of us would take vacation during that time because the phones just wouldn't ring for those 2 weeks. Same with Christmas shutdown. The one thing I miss about that job was that no one ever called you or emailed you during those 2 shutdowns. You really got to take a break and no one was going to bother you. Ramp up was always slow after that.
Now I work in a different manufacturing sector. I am finding that the Mid-west seems to shut down according to the hunting season. No joke - at least for Missouri. Our reps out there would tell us it was "gun season" or "bow season" that week and everyone was gone.