Keep in mind that if you get a car at the end of the model year, the value of the car will be group with those sold at the beginning of the model year. The resale value would be lower because your car would be considered a year older. This wouldn't matter if you intend to keep your car.
Also, if you wait until the end of the model year, the selection in colour and options would be limited.
For any particular car, find out when the model year starts. I think they usually start around September. However, I've seen new cars come to the market in less than 12 months.
As already mentioned, month or quarter end is a good time to negotiate. Even Toyota have quotas to meet.