We know, we know: Timing is everything. But when it comes to being a smart shopper, the old adage is especially true. Knowing when retailers will mark down the items you need and want can translate into serious savings. Not to mention that you’ll look like some sort of psychic shopping genius.

We asked for what-to-buy-when tips from experts and plumbed sources such as FreeShipping.org’s Best Time to Buy Guide to come up with a seasonal shopping list. Here, the buys that will get you through the end of summer under budget.

- Now’s the time to invest in summer suits, as stores clear out inventory to make room for fall merchandise. If you need a winter suit, don’t miss Nordstrom’s annual anniversary sale. Fall items are marked down until July 31.

- Butter production spikes in June and July, so stock up on it now. You can freeze it for up to six months, which will even out costs when holiday-baking time rolls around.

- With few bubbly-worthy holidays on the horizon, look for discounts on sparkling wines.

(bigstockphoto)

- No sane person would want to be outside painting now, right? Maybe that’s why retailers slash prices on interior and exterior paints in the late summer — but whatever the reason, now’s the time to buy supplies for those cool-weather DIY jobs.

- If your living room is starting to look a bit lackluster, end-of-summer furniture sales couldn’t come at a better time. New furnishings usually arrive in stores in February and August, so capitalize on retailers’ need to offload past-season styles when they slash prices this month.

- Summer might be half over, but there’s still plenty of time for outdoor entertaining. Now that Memorial Day and the Fourth of July have come and gone, grills get serious markdowns. Check your local big-box retailers and GrillsDirect.com, which has lots of models on sale and offers free shipping.

- If your back yard needs a facelift before you invite guests over, scoop up patio furniture now. Retailers start moving leftover outdoor furnishings to clearance about mid-July.

- After holidays is a great time to score large appliances. Save 10 percent on a kitchen system worth $2,500 or more at Ikea’s kitchen sale, which runs to Aug. 21. Add appliances and save more. “After Independence Day, most big-box retailers are trying to dump their inventory, so you can get refrigerators, washers and dryers up to 30 percent off,” says Allison Kade of personal finance site LearnVest.com.

- Get ahead of the holiday rush and scoop up a lower-priced gym membership now. Bonus? You’ll be in the workout habit before it’s time to work off the Christmas carbs.

- You’ll probably see discounts on older-model computers and MP3 players, as updated versions land on shelves in early fall. “Retailers are trying to sell off older models before October, when the holiday rush starts,” Kade notes. “But if you want a newer model, wait until September, when you’ll see discounts timed for back-to-school,” says Maria Lin, LearnVest’s editor in chief. Lin points to Apple’s current deal: Get an education discount and save $50 to $200 on a new Mac, and get a $100 gift card to use for apps, music and e-books.

- If you don’t mind storing them, pick up discounted swim accessories, from swimsuits and goggles to kiddie pools and squirt guns, as retailers clear out stock at the end of the summer. The same goes for camping gear.

- You might be anxiously awaiting the end of grass-cutting for the season, but don’t overlook deals on lawn mowers this month. Mowers and other gardening equipment take up room on the sales floor, and they’ll be marked down to make room for new arrivals.

- Nurseries and other greenery outposts will start discounting summer plants and flowers as gardeners look ahead to the fall planting season. Scoop up the stragglers, making sure to look for ones that can handle a bit of hot weather.

- Retailers cut prices on linens, desk organizers and storage containers in the hopes of attracting college-bound consumers.

- School supplies drop in price at the end of the month, with some stores offering dirt-cheap deals. Keep in mind, however, that coveted or name-brand items, such as backpacks, can sell out quickly.

The Bottom Line: Timing your purchases around the retail market’s ebbs and flows will help you reap the biggest rewards. Make note of when new merchandise arrives to take advantage of discounts on past-season goods. Stock up on supplies for next summer — and the last few hot weeks ahead — as retailers slash prices on current stock in the next several weeks.