Nobody wants to be that guy when he goes on vacation. You know, the tourist who sticks out because he's all pale and weighed down by cameras or, worse, breaks some kind of coolness code that keeps him — but not his significant other — from getting into a swanky nightclub.

But did you know even details as subtle as the bright plaid board shorts you bought a few years ago could brand you as an outsider on a California beach? Oh, and if you were thinking about wearing a howling wolf T-shirt to go camping in the Rocky Mountains, pfft. Even the wildlife will be mocking you.

From the laid-back swagger popular in coastal towns to the style-savvy trendsetting mentality on the streets of New York, unwritten fashion codes help decipher who is local and who is — how do we say this gently? — a tourist dork.

Because the travel guidebook you checked out probably doesn't offer fashion tips, we asked trend and style insiders from major vacation destinations to reveal what's hot — and what's not — in their cities.

BIG-CITY EXCURSION

The Big Apple is all about big style.

"People really make an effort here," said Julie Rath, founder of New York-based men's image consulting and personal styling firm Rath & Co. "They're not afraid to try new trends and looks, which makes the city quite interesting visually."

And, yes, the cliché is true: The chic people of New York wear a lot of black, too.

Bomber jackets are trending big this season, she said, offering a trimmer, more modern take on the traditional cut of a varsity jacket. "I especially like them in sumptuous fabrics like suede and soft leather," she said.

Indigo is an "it" color this season. Rath describes it as a "next-level navy" and says it looks terrific in a linen or hopsack blazer or in the form of a chambray dress shirt.

Her style tips for nightclubs and restaurants: crisp dark jeans and a sport coat. Extra points for a pocket square.

"For an informal setting, try a henley under your sport coat instead of the expected button-up shirt," she said.

Some New York-style no-nos: fanny packs, no matter how convenient they might be; socks pulled up to your calves; socks with sandals, and wearing athletic sneakers for non-athletic activities.

BEACH VACATION

Southern California style is all about channeling a cool, laid-back look without seeming like you tried too hard. Which, actually, seems kinda hard. That's why we've called in help from Beau Flemister, managing editor of Surfing magazine.

Tourists flocking to the Golden State start at a bit of a disadvantage if they're without a golden glow.

"You're already going to stand out if you're super-pale," Flemister said.

So don't accentuate your brightness with look-at-me neon and floral prints on swimwear. Really baggy swim trunks are also "out."

Trendy surf trunks this year include above-the-knee styles cut a little tighter than in the past, and iconic prints (think small giraffes or cheetahs), Flemister said.

"Ten years ago, it was all about skull prints," he says. "You saw them on everything. Then it was all about plaid shorts. Now people are going back to more faded pastels or earth tones."

MOUNTAIN GETAWAY

Erase all images you have of mountain men clad in lumberjack plaid.

Constance Golder, an Aspen, Colo., stylist whose client list includes People magazine, T.J. Maxx, Oakley and the Aspen Art Museum, suggests incorporating elements of citywear when you're visiting a mountain town.

In other words, don't try too hard to look "outdoorsy."

"You don't have to change your keychains out for carabiners," she said. "Be yourself and incorporate mountain style into who you are."

A common style faux pas she notices in mountain towns? "I see guys walk around in pajamas and T-shirts," Golder said. "They somehow interpret the mountains as an excuse or license to totally slack off."

But putting together an outfit that looks good can be easy, she says. Straight-cut jeans and polos are a winning combination, in her book. She points to $45 flat-front shorts from Gap that come in a variety of colors as an affordable staple. And pack an extra pair of shoes, Golder said, noting she's partial to a neutral suede shoe or colored wing tips. She also suggests a dark wash, well-fitting denim jacket.

Oh, and, wear Spandex with discretion.

"Please don't walk around in your bike shorts," she said. "It's not a good look on anyone."