Nothing refreshes during a sizzling day outdoors quite like chilled, sweet watermelon, juices running down the arm and dripping from the chin.

But for so many of us, enjoying a sweet melon — or peach or orange, for that matter — is happenstance. Theories for selecting sweet fruit abound, to the point of being contradictory and confusing. Flick a melon. Don’t flick — thump. Examine the stripes. Stripes have nothing to do with it. Look for brown spots. Avoid blemishes.

It’s enough to drive a fruit lover wacky.

With summer officially upon us, we decided to go to the experts — farmers and grocers who make their living providing the season’s bounty. Here’s what they had to share:

MELONS
(Courtesy Kae Sou, vice president and controller,Aloun Farms; and James Channels, director of produce, Foodland)

Melons comprise acid and sugar. When you leave a melon out to "ripen," what’s really happening is that acid levels — which are sour — drop, leaving only sugar. Melon season runs May to October.

>> Honeydew: For sweetness, the uglier the better. Look for a fruit with brown lines, called sugar webbing, which indicates the presence of sugar.

>> Cantaloupe: A yellow hue means the fruit is ripe. Thick netting on the rind indicates it’s more mature. Look for that winning combo.

>> Watermelon: Forget about listening for a specific sound, examining stripes or pondering yellow spots. It’s all about feel: Rest one hand on the side of the orb, then tap it on the other side with the other hand. You should feel a vibration in both hands, which means there’s a lot of water inside, indicating juiciness. No reverberation means the fruit inside is overripe and mushy. Aloun Farms picks its watermelon ripe. It will last up to a month in the refrigerator.

STONE FRUIT
The season for stone fruit runs roughly from late May through mid-August, peaking about mid-July.

>> Tree-ripened edge: Growers that prioritize flavor will keep fruit on the tree as long as possible, allowing sugar content to develop. Even fruit picked before it is fully ripened (as is fruit bound for Hawaii) can be sweeter if the process starts on the tree.

"This allows the fruit to develop all its natural profiles — the characteristics of its flavor," says Channels. Such fruit may require just a few days on the counter to complete the process.

Foodland and Kokua Market source their stone fruit from growers committed to this process. Foodland works with Kingsburg Orchards, and Kokua partners with Alberts Organics, both of California.

Some stone fruit shipped to Hawaii is artificially ripened with ethylene gas, according to Ken Love, a Hawaii expert who specializes in tropical fruit. While such fruit may take on a nice color, "it will never get any better than what it already is," said Love.

All experts agree: It’s important to know where your fruit comes from.

>> Color, aroma and feel: Ripe nectarines, peaches, plums and apricots should "give" a little when gently pressed, meaning the flesh feels a bit flexible. It shouldn’t be hard like a baseball. But soft pressure shouldn’t puncture the flesh, either. Plums in general are softer than nectarines and peaches, while apricots are harder.

Ripe stone fruit will also have nice color and a perfumy aroma.

July is peak cherry season, says Channels, and that’s when Foodland will begin carrying cherries from Washington state, a prime spot for producing delicious fruit. Right now, red cherries from California are on shelves.

ORANGES AND STRAWBERRIES
(Courtesy Kae Sou, Aloun Farms; and James Channels, Foodland)

>> Oranges: Orange season usually runs from November to June. With mainland oranges, it’s hard to assess sweetness through color, Channels says. But a good orange will have "a little give" and weight, indicating juiciness. A smooth rind indicates maturity, which could also contribute to sweetness.

Locally, Aloun Farms has 100 orange trees on 12 acres — too little for mass production but enough for farmers markets. Aloun’s orange season runs from October or November through February. Sou says that when it comes to selecting the variety known as "Kau oranges," "the uglier the better. If they’re super nice yellow, they’re sour. If they have brown lines and ants are making holes in it — they like the sugar — you know they’re sweet."

>> Strawberries: Channels says to beware of "white shoulders," white flesh over one-fourth of the fruit. This means it is underdeveloped. On the other hand, dried tops indicate the berry is old. Color is not an indication of sweetness; light-colored berries can be good eating.

WHAT’S IMPORTANT?
Sou says supermarkets juggle various priorities for the fruit they display.

"Supermarkets pick for appearance and display, so the fruit must be nice-looking," she said. "They can also prefer larger-sized fruit."

Sou says she takes smaller melons, called "personal-size melons," to farmers markets. (Aloun has booths at Kapiolani Community College’s Saturday market and Dole Cannery Square’s Friday market.) These fruits are especially sweet, and Sou selects them herself for customers she has gotten to know.

Ultimately, she says, sellers will offer what customers ask for, so share your priorities with your grocer.