When is the best time to buy a new car? as far as discounts and rebates...?
Historically, manufacturers have steadily increased rebates on the current year models thru July 1st. Keep in mind what rebates are for. They are designed to create incentives early in the year to motivate buyers, and then as the season moves into summer, the increasing rebates help to make room for the new models arriving on the lot. You don't see much movement on rebates after July because there is little reason to. Most of the models will be gone by September and there's no real incentive to jack up rebates just to move a small handful of cars.
This is my recommendation to new car buyers. Wait until July 1st to buy your new car. Available car inventory in the market will still be strong, and you'll have good choices left. If you wait too long and it gets late in the year, there won't be much left out there. When November rolls around and you've just started shopping for the red truck you wanted, you might be faced with choosing between the last two white trucks in your entire region. That might not make you too happy. So while a year end deal might seem like something worth waiting for, it's a total long-shot that there will be anything left to buy at all. Wait for July 1st, and then go shopping.