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If you’re planning on ponying up for a new car this year, know that certain months may be lighter on your wallet than others.

Avoid Spring

Spring is the least budget-friendly season; warmer weather attracts people eager to spend after enduring a lengthy winter, especially if they have tax refund checks in hand. But in summer, fall, and winter, the laws of supply and demand are more nuanced. The optimal time to head to the dealership depends on what you want to buy.

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Inventory moves slower in winter, leaving dealers more likely to cut a deal. They’re also incentivized to clear their lots in the summer to make way for next year’s models. Those incentives tend to extend into the fall, as automakers continue to rollout future releases. Regardless of the season, you’re likely to get the best deal on a vehicle when demand for the segment is slow, so time your convertible purchases for the winter and robust SUVs and pickup trucks for the summer.

August Is Ideal (If You're Not Buying Luxury)

The sweet spot for non-luxury vehicles, according to industry insiders, is August, especially if you’re searching for the current model year. Dealers start receiving shipments of next year’s models during the summer and are in the thick of summer sell-down promotions by August, when they face mounting pressure to clear the lot for incoming inventory. But it’s not so late in the year that the current year’s models are in short supply. Instead, August is when you are likeliest to find a vehicle with the color, trim, and options you want.

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Toward the end of the year, inventory thins and finding your dream configuration gets more difficult. Note that you’ll get the best deals – sometimes shaving four-figures from the MSRP – on models about to undergo significant redesigns. Buying the current model year means your new car might lack the latest styling and technology, which could lower its resale value if you plan on selling it within a few years.

December for Luxury

For luxury purchases, the best month to buy is December. “All of the manufacturers are trying to meet or beat their sales forecasts,” says Melissa Steffy, general manager at Herb Chambers BMW in Boston. That’s when you’ll be able to snag the deepest discounts on the current year’s luxury leftovers. But you won’t be able to afford to be as picky as you could be earlier in the year because dealerships have fewer options on hand.

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Regardless of the month, common wisdom holds that the fourth week of a month is generally a better time to buy than during the three weeks prior. Some auto sales professionals say that the last weekend of the month is a sweet spot, as dealerships look to take advantage of the uptick in foot traffic. Note that December isn’t the only time dealers and sales associates need to strive to hit year-end sales quotas. They also have to hit their targets at the end of each month and the end of each quarter. That means you’re likely to get a deal at the end of the month and an even better one at the end of March, June, September, and December when the fiscal quarter concludes. Oftentimes, you won’t have to wait until the very end of the month or quarter to reap the benefits, however. Dealers begin preparing to meet their quotas a few days in advance, so it’s possible to get a head start on those negotiations.

Between Christmas and New Year's

The single best week to purchase a new vehicle is between Christmas and New Year’s because, as Herb Chambers BMW’s Steffy points out, general managers and sales associates are trying to meet personal and dealership-wide end-of-year sales quotas. The final week of the year intensifies competition on all fronts: Automakers give dealers significant payouts to move the current year’s models from their showroom lot to your driveway at the end of the year. Many general managers and sales associates will be aiming for that bonus, so they’re more willing to offer you a better deal. They’re also likelier to make you a deal in anticipation of the annual winter sales slowdown in January and February. In addition to the incentives and deals they promote to attract customers, there’s usually also ample inventory from closeout models, giving customers more choice on additional bargains.

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“While the best month to buy a car depends a lot on market conditions -- how sales are doing, where interest rates are – December, particularly the week between Christmas and New Year's – typically has the lowest transaction prices, as dealerships look to end the year on a strong note, and most people aren't shopping then,” says Jamie Page Deaton, managing editor of U.S. News Best Cars. “When you add year-end deals to your already strong negotiating position, you end up having a great chance at saving a lot on a new car.”