When it comes to discounts and deals, September can be a tricky month as businesses transition from their Summer savings promos to their Autumn offers. Thankfully, DealNews has sorted out just what is worth the spending this month and what is worth the wait.

September is an odd month for shopping, since Summer has officially come to a close, and we're inching ever closer to Black Friday. But September has its own deal virtues, including Labor Day sales! So we've mined the extensive DealNews archives of sales, coupons, and individual products from the past few Summers to find out what are the best and worst things to buy in September. Read our guide, and be sure to sign up for the DealNews Select Newsletter so you don't miss one of the best deals.

Keep an Eye Out For Lingering Labor Day Sales

Typically, holiday weekend sales start early — sometimes very early — and Labor Day is no exception. However, most run through the holiday itself, and several will trickle into the first week of September. Look for discounts on grills, patio sets, mattresses, and luxury clothing. For more details on what to expect, check out our full Labor Day buying guide.

Patio Furniture Deals Are Sitting Pretty

Speaking of patio furniture, it's finally a great month to buy these items, during Labor Day sales and beyond. September will see an increase in the sheer number of outdoor furniture sales and deals on seasonal outdoor items. Look for discounts from retailers like Target, Lowe's, Kmart, and Sears, with discounts of 50 percent to 75 percent off clearance outdoor furniture.

Get Your Caffeine Fix For Free — Stock Up on K-Cups Before Price Hike

If you're a devout coffee drinker, then make sure to mark Sept. 29 on your calendar, as several food chains will offer a free cup o' Joe in honor of National Coffee Day. In years past, Dunkin' Donuts, Krispy Kreme, 7-11, and Caribou Coffee all offered special promotions to celebrate, and it's possible that other chains and local cafes will do the same this time around, too.

And while we're on the subject of coffee, Keurig fans will probably want to spend September and October stocking up on K-cups; the manufacturer announced that it will be increasing prices by 9 percent starting on Nov. 3. And keep in mind that while owners of older machines can just turn to other brands for K-cup-compatible options, newer machines are DRM protected, so some of us are stuck with what Keurig is selling.

New Car Models This Month Mean Good Deals in October

Since many manufacturers release new car models in September, experts in the industry claim that dealerships will start slashing prices on older models. These discounts exist in September, but according to Forbes, they become substantially better in October and later. As such, you can save 10 percent to 20 percent or more on a current car if you wait until October. And don't forget these other tips for securing a better price on a car while you're at the dealership for the potential to save even more.

No Considerable Savings on Large Appliances Yet

Conventional wisdom says to buy large appliances in September and October, because this is when manufacturers like LG, Maytag, and Whirlpool debut their new models. However, unlike cars, our archives show that you'll see at least double the number of Editors' Choice deals on these items in November because such items will be included in Black Friday sales. This has held true for the past three years. Be on the lookout for discounts on washers, dryers, vacuums, and the like from department and home improvement stores.

An iPhone Announcement Will Lead to Price Cuts and New Models

As is tradition, Apple is expected to announce a new iPhone this month, on Sept. 9, which means that previous generations of the iPhone are about to receive a price cut, in one form or another. Traditionally, Apple had been keeping the $199 model in rotation by dropping it to the $99 price point, and the $99 model to $0; however, last year it debuted two new models for $99 and $199, and it seems likely that it will do this again. We're guessing that the iPhone 5c will drop to $0, while Apple will eradicate the 5s entirely. Wireless providers that are stuck with remaining iPhone 5s stock will likely price it under $100 to move inventory, making it possibly the best value in the coming weeks.

TV Deals Show Signs of Life, but You Might as Well Wait Until November

Autumn is upon us, and with it comes the return of our favorite sports and TV shows. While that alone may tempt you to invest in a new HDTV, we're roughly 60 days away from Black Friday season, the absolute best time to buy a new TV. So we're recommending consumers hold off a few more weeks before purchasing a new TV.

That said, HDTV prices are already slowly improving this month. Name-brand 42" HDTVs, for instance, hit their lowest mark of the year last month at $285. These sets are currently cheaper than they were last holiday season, although we expect prices to drop further come November. Name-brand 55" TVs have also taken a nose dive at $550, which is $65 under this year's average for that category. As we discovered recently, Dell Home is a great place to look for deals on name-brand TVs.

Fall will also kick off a wave of deals on TVs with premium features. For instance, in late August we saw a 39" Seiki 4K HDTV for $280, which is the cheapest 4K TV we've seen in any size category. While there's a multitude of reasons to avoid 4K, this deal indicates retailers are eager to move their inventory, and this holiday season budget 4K HDTVs could steal the show. In a similar fashion, Sony has discounted its 65" Curved 1080p 3D LED LCD from its debut MSRP of $4,000. It hit a low of $1,800, and is now up to $2,500, but that's still 38 percent off. However, curved displays are also a nascent technology and have yet to prove their worth.

Nevertheless, prices on both technologies are volatile, and shoppers interested in these sets would benefit from waiting a few months before jumping on any deals, as tempting as they may seem. After all, these aren't the kind of items that increase in value over time, as we learned all too well from this hilarious clip from the Antiques Roadshow.

Mainstream Laptops Continue Price Descent

You may find some residual back-to-school deals in September, but generally speaking, the season is over, and the next best wave of noteworthy laptop deals will come in November. (If you're still looking to buy for college, whatever you do, do not buy from your university book store without doing some comparison shopping first.) However, retailers may continue discounting mainstream machines, i.e. 15" systems with Intel's current-generation processor, as these laptops hit $360 in late August. That's $63 under this year's average for that category. Leading the discount charge is online retailer Newegg, which has been consecutively dishing out the best laptop deals since June.

Apple's back-to-school sale will end on Sept. 9, but even if you miss it, there's still a chance you can grab a heavily discounted 2014 MacBook Air if you have a valid .edu email and frequent Best Buy, which has trumped Apple's back-to-school MacBook Air prices all Summer long.

Ready to put this information to use? Sign up for the DealNews Select Newsletter or download the DealNews app in order to keep abreast of any and all of these best buys in September.

— Lindsay Sakraida