Kelvin Natural Slush.

It is way too early to be thinking about the summer. It’s mid-April—taxes are behind us, Memorial Day looms far off on the horizon and you can’t walk past a garden in bloom without stopping to exclaim, like a 4-year-old, “Flowers! Pretty!” No way is it time to think about the summer yet.

But. There’s a fine line between spring and summer, especially in New York, where the one can notoriously blend into the other in the blink of an eye. This week saw an uncomfortable preview when the temperature spiked on Monday to a near-record high, and even on steadier days, the midday sidewalks feel positively equatorial.

There’s a fine art to this slippery semi-season. You can’t leap right into summer standbys; there are a solid four months of real heat ahead, and anything you start doing now will be worn threadbare by Labor Day. Though we’re champing at the bit to unpack the sandals and shorts, that way madness lies. You must save yourself somewhere to slide to when August humidity turns the subway into the world’s most unpleasant rainforest—then and only then can you bust out the flip-flops and eat pints of Ben & Jerry’s with your head in the freezer.

Right now, even frozen treats should be refined, delicate, virtuous; a minor thrill in your spring-cleaned day, still healthy and light—the cherry blossom to August’s overblown gardenia.

The drinks from the Kelvin Natural Slush Co. (various locations, find them daily at @kelvinslush or this Sunday, April 22 at the Hell’s Kitchen Flea Market Gourmet Food Truck Bazaar, 39th Street & 9th Avenue) are Vendy Award-winning Slurpees that come in flavors actually found in nature. More reasonable beverage than gut-busting dessert, their ginger, citrus or tea slushes are all perfect for sipping on an afternoon stroll. If you’re feeling feisty, add one of their fruit or herb mix-ins for a grownup version of Coldstone Creamery’s candy-coated free-for-all. Caramelized pineapple in the spicy ginger base is a match made in tropical heaven; add basil for an unexpectedly sophisticated kick.

The Soft Serve Fruit Company (1371 3rd Ave., at 78th St., or 25 E. 17th St., at Broadway, www.softservefruitco.com) is just what its name implies, to shockingly good effect. It’s just fruit, water and cane sugar, but the texture they get out of their magic machines is light years from that time you tried to make “instant ice cream” by pulverizing frozen bananas in your food processor, shorting the engine in the process. For everyone who’s ever cursed sorbet for being too icy and hard to scoop, this is a revelation. Banana is the most treat-like, especially when topped with crushed pretzels and warm peanut butter or maple syrup (yes, it’s natural, but I never said it was virtuous), but mango and strawberry are simply delightful, no adulteration needed.

A proper Italian affogato is a perfectly respectable adult diversion, no kid’s bribe wrapped in classy packaging. OK, so it’s gelato, only a tiny linguistic step away from ice cream. But it’s a dainty portion of the stuff that is drowned in a shot of espresso, less blowsy than a Starbucks Frappuccino and far more satisfying. At Maialino (2 Lexington Ave., betw. 22nd St. and Gramercy Park, www.maialinonyc.com), a Roman-styled trattoria perfect for leisurely lunches or a midday pick-me-up, the gelato is fior di latte, sweet milk, and the espresso is dark and rich. Dawdle over this with a tiny silver spoon, watching the opposing textures merge and meld into a third while gazing upon the gated glory of Gramercy Park.

Enjoy these now while your sanity lasts and you can still appreciate something more flavorful and interesting than the blunt-force frozen trauma of a Mister Softee cone. After all, those spring blossoms are already dropping fast—didn’t somebody once say something about gathering rosebuds while ye may? This is definitely what he meant.

On the west side of Broadway at 95th Street sits Peaches Natural Yogurt Café, directly across from The Lite Choice (TLC). Walk over to the east side of Broadway at 94th Street and there is a Tasti-D-Lite in the middle of the block. All are Kosher and tout their low-calorie status.

“The day Tasti opened, both stores”—Tasti-D-Lite and The Lite Choice—“were offering promotions. It was like an ice cream war,” said neighborhood resident Hillel Spinner, who favors TLC and is partial to peanut butter. “It tastes almost like real ice cream, only it’s light and I’m health conscious.”

Prior to September 2008, the location where TLC now sits was a Tasti-D-Lite. According to TLC president and CEO Ron Greenstein, when Tasti-D-Lite became a franchise, he and his partner Ed Newmark decided to create their own brand of soft-serve and organic flavors, trademarking it “TLC, The Lite Choice.” A four-ounce serving ranges from 85 to 120 calories, depending on the flavor, and is low-fat, low-carb and lower calorie.

While TLC has its fans, there are still many diehard Tasti-D-Lite lovers, which is one of the reasons the company opened up a new and larger operation on West 94th Street, according to Lindsay Held, the company’s area developer for the Manhattan territory. The branch has been operating since Sept. 27.

“We plan to focus on what we do well,” Held said. “No frozen dessert brand offers the creaminess of Tasti-D-Lite. Our dairy-base mixes do not contain artificial sweeteners and it has much less than half the sugar of the leading frozen yogurt chains.”

Tasti-D-Lite’s four-ounce serving ranges from 85 and 100 calories.

Peaches Natural Yogurt Café, just a few doors away from McDonald’s on West 95th Street, has been in the area the longest; the store celebrated its year anniversary this past September. Robert Jang said he and the other four owners had been looking for a location for a while, so when this spot opened up they grabbed it. At the time, a Tasti-D-Lite was across the street (it’s now the TLC), but he said they didn’t consider it a competitor.

“It’s a different product,” Jang said. “There are no other stores close by that offer a similar product. Two in ten customers walk in and think we sell the same stuff, so we give them a sample, and if they don’t like it we send them across the street.”

Unlike the other two frozen dessert chains, which offer a wide range of flavors, Peaches offers just four: original, Euro-Tart, Green Tea and one floating selection, ranging from banana to cappuccino. A four-ounce serving ranges from 60 to 120 calories. All the flavors are non-fat with the exception of peanut butter, which is low fat.

“Our product tastes like Greek yogurt and the Europeans love it, especially our Euro-Tart and Green Tea,” Jang said.

While customers in the neighborhood seem to have strong opinions about which frozen dessert they like best, the question remains, will there be enough business to keep all three stores afloat?

The business owners seem hopeful. TLC has begun offering a successful seasonal product early—Lite Hot Chocolate—to give customers another reason to stop by. Tasti-D-Lite is rolling out new products, like hot granola and a Fruit N’ Granola Parfait. And after struggling last winter, when Jang said that Peaches was “dead,” he is hopeful that things will be different this year, especially now that the scaffolding that once hung over his store is removed. He and his partners are planning to open another store this winter on the Upper East Side.

Not everyone is so optimistic, however.

“The chances of any three similar businesses within one block staying in business in this economic environment are pretty slim,” said Jay Streich, president of Quality Living Inc., a licensed real estate broker with offices on the Upper West Side and downtown. “I’m sure one will stay open.”

Resident Sandra Carballo was equally pessimistic.

“It doesn’t make sense to me. I don’t see how they can all survive,” she said. “Maybe if one of them starts selling sandwiches and soup or something. Otherwise they are just too similar.”