It's hard to figure out what to wear this time of year. One day you're in shorts thinking summer is here, and the next you're dramatically underdressed and running across the street to find some sunshine. Taking a cue from temperature-varying sports like skiing and hiking, the best solution to this problem is to dress in layers. Throw a light sweater on between your shirt and your blazer; add a scarf over your T-shirt and put a cardigan on over that; or, as one guy I saw did, wear a shirt and tie with a sweater over that, with a cardigan over that with a sweatshirt over that. I'm sure that sounds crazy, and I acknowledge that you would need an accomplished sense of proportion to pull that off, but trust me, he did.

Aside from matters of temperature, wearing layers can also be an opportunity to show more sides of yourself through your clothes. My favorite example of this is a photo of Richard Gere from 1980. Had he been wearing only the denim shirt and tweed blazer, he would have looked like your average prep school throwback. But with the addition of a pink zip-up sweatshirt, he looks sportier, younger, and less predictable. Wouldn't you love to give a first, second, and third impression all in one look?

It's hard to believe that this guy has four tops on and still looks good, but he does. Mott Street, NYC, January 2008.

I went to my husband's family farm in England for Easter weekend and we had some friends to stay. One of them follows my blog and asked what my next theme was, and I told her it would be the evolution of hooded sweatshirts. She didn't get how they fit into the Men's Vogue worldview. Elaborating on what I had already begun to uncover in my research, she explained that in England hooded sweatshirts, especially when worn with the hood up, had downgraded from urban or athletic streetwear to an active display of aggression and malice. So much so that if she saw a guy walking down the sidewalk with his hood up, she would steer clear and cross the street. Furthermore, many malls across the country have banned hooded customers from the premises, since thieves were using their hoods to mask their identity from security cameras.

From my perspective, it seems the opposite has happened in America. Here, hoodies have migrated from sportswear and inner-city status symbol all the way up to standard "well-dressed white guy" fare. I see guys using hoodies to add a bit of street cred to an otherwise too formal, too serious blazer and button-down-shirt look. Others wear them merely to keep warm -- a more casual incarnation of the wool scarf. My friend Josh, who is a writer, almost always wears some kind of sweatshirt with his tweed blazer, well-loved Levi's, and wingtip shoes. If he's going out to dinner with a friend or to lunch with an editor he'll wear a crew neck sweatshirt with his everyday look, but for the weekend he dresses the whole look down with a hoodie. If only everyone had such a simple formula for getting dressed.

Heavyweight champion Muhammad Ali trains for his title defense match against Sonny Liston in a hooded sweatshirt. (Ali won the match with a first round knock out that came to be known as "the Phantom Punch" in one of the most controversial fights in boxing history.) It's hard to believe this classic athletic look would be outlawed today in England. Lewiston, Maine, 1965. (Image: Getty)

I just can't help it. When I think about men wearing cardigans, Mr. Rogers pops up in my head, hanging up his sweater at the start of every show. It's a wholesome look, for sure, but that's all the good I can say about it. So needless to say it wasn't my idea to do a blog about cardigans. It was my assistant Chelsea's idea, and when the subject first came up, I'm sure I made a suspicious face. But because Chelsea's instincts are usually spot-on, I promised her I would keep cardigans on my mind while man-scouting.

I've now had a few months of cardigan observation, and I have seen enough guys doing it well to convince me that it's a look that absolutely works in today's context. A Fair-Isle sleeveless cardigan worn with a button-down shirt was toned down by rolled jeans and flip-flops; a shaved head seems to do wonders to counteract the inherent fifties "ideal husband" look; and, in one case, silver Vans (I know it sounds weird) worked to lessen the overt preppiness of a primary-colored striped cardigan.

It may have been Kurt Vonnegut who, once and for all, sealed the deal on cardigans for me. A picture I found of him in the seventies made it clear that the disheveled cardigan is by far the most masculine cardigan. And while it is possible to look good in a tidy, buttoned-up cardigan--as British jockey Billy Cook did in the late forties--it does require you to keep Mr. Rogers out of your neighborhood.

   I like how casual and not overly considered Kurt Vonnegut looks in his clothes. I don't know what he wore all the other days of his life, but this would have made for a good daily uniform. There's something very attractive about men who know themselves well enough to figure out what suits them and stick with it. 1970s. (credit: Getty Images)

Just from looking at his athletic build and shaved head, I would have never suspected this guy would be a cardigan wearer. He looks great though. Mercer Street, NYC, October 2007.

I LOVE the sweater-as-jacket idea that this 1950s school boy has adopted. (credit: Getty Images)

A friend sent me this picture. It took me a moment to see why this guy's look was remarkable. Then I realized that his tux jacket was actually a knit cardigan. I've never seen this before. I'm really into it. Ludwig Heissmeyer at the Metropolitan Museum of Art, November 2007.

David Hockney shows a more artsy side of the cardigan look in his studio. 1978. (credit: Getty Images)

I can't quite figure out what this guy was trying to accomplish with his hairstyle, but I like his outfit a lot. Spring Street, NYC, October 2007.

Legendary Penn football coach and Heisman trophy namesake John Heisman shows us the masculine extreme of the cardigan spectrum. 1920. (credit: Corbis)

This guy clearly has his own think going on--prepster on top and hipster on bottom. I can get with it. Broadway and Prince Street, NYC, June 2007.

I love this guy. It's Ian Gillian, lead singer of a band called Deep Purple. I've never heard of him or his band, but his layered sweaters with the contrasting long hair and classic watch look particularly good. 1971. (credit: Corbis)

Famed Art Historian Meyer Schapiro stands for his portrait in a more academic layered-sweater look in 1981. (credit: Getty Images)

While I wouldn't necessarily recommend wearing a wool fisherman's cardigan with nothing underneath, Elliot Gould (shown at his opening of Drat! The Cat! with his then-wife, Barbra Streisand) stands out from all the other pictures of men in cardigans--so I felt he deserved some attention. 1965. (credit: Corbis)

My editor, Ned Martel, is a confirmed cardigan enthusiast--although I didn't know that until recently because I rarely see him in his office. So I made the trip to catch him in action. The Conde Nast building, Times Square, NYC, November 2007.

Prince Philip leads his carriage team back to their paddock at Windsor Castle after the Royal Windsor Horse Show. His look is about as old-school English as you can get. 1973. (credit: Corbis)

Thomas Ince, the silent film director and producer who died mysteriously onboard the yacht of William Randolph Hearst, shows that the cardigan-as-jacket idea goes way back. 1918. (credit: Getty Images)

This guy's look is somewhere between Chariots of Fire and a Prada store salesman. I hope it reads as more the former than the latter. Prince Street, NYC, July 2007.

Legendary Blues musician Little Walter defines sixties cool. Its the soul version of classic menswear. Theresa's Lounge, Chicago, IL, early sixties. (credit: Getty Images)

This guy was better in person. He must have been frightened by having his picture taken because he looked great walking down the street. I hope his modern take on preppy comes across. Lafayette Street, NYC, August 2007.

You must know by now that I love Bing Crosby's cool cat style. Seeing him in a cardigan AND standing next to David Bowie hits it out of the park for me. 1977. (credit: Getty Images)

Australian jockey Billy Cook (in a sporty fully buttoned-up cardigan) with trainer Walter Nightingall watch an exercise session at Epsom Race Track, England, 1949. (credit: Corbis)

There's one thing that might finally topple the so-called rules of seasonal dressing: global warming. I'm already beginning to notice the absurdity of men feeling like they can't wear white or linen or shorts after Labor Day when it's 80 degrees out in late October. And while the dictators of convention may not be ready to make an official change in the etiquette book, I like the idea of men prolonging summer in their wardrobe (or maybe getting an early start on spring?) by wearing unseasonably bright colors.

A lavender sweater, for example, has a different feeling when worn in June than it does in October. The common perception is that if you're wearing bright colors in warm weather, then you are joining the masses, becoming part of the norm. It seems like a bigger commitment, however, to wear, say, red pants on Madison Avenue after Labor Day. Did someone say dandy? I hesitate to label it that way because--while there's nothing wrong with being a dandy if that suits your style--there is a way to be colorful in the later months of the year without feeling like a peacock.

The most obvious way to wear color off-season is to add just a hint of it--an emerald-green pocket square, a duck-egg-blue tie, or if you're a free-spirited artist like David Hockney, even two different colored shoes! The men who wear full-on jolts of color--a tangerine sweater or a fire-engine-red military coat--look best when the rest of their outfit is toned down and neutral. Mind you, there is the rare exception, like the sixties image of English photographer Patrick Lichfield looking confident and enviable in a purple shirt with canary-yellow pinstripe pants. But take on looks like that with caution--even if you're dressing for springtime at Thanksgiving, you still don't want to look like an Easter egg.

The shopkeeper at Richard James in London (my favorite men's store) knows how to wear intense color to his advantage. Savile Row, June 2007.

I love seventies pictures of the British royal family--obviously the Windsors were never trendy, but a laid-back vibe seems to have seeped in. Note the longer hair and the orange sweater. 1978. (Getty Images)

My friend Carlos Mota, in color coordination with my daughter Coco's riding chaps. Oxfordshire, England, 2007.

Charles Dana, the founder of the Lyford Cay Club in the Bahamas, in a preppy linen blazer. 1983. (Getty Images)

This Ralph Lauren employee would look pretty run-of-the-mill without that pop of emerald. East Fifty-ninth Street, NYC, October 2007.

British one-hit wonder Whistling Jack Smith wears a recycled bright red military jacket. The cloudy fall weather makes a good backdrop for the intense color. 1967. (Getty Images)

Before he brought the world Cosby sweaters, Bill Cosby fought the winter gloom with a yellow turtleneck. 1966  (Getty Images)

Have you noticed that I have a thing for dark-skinned guys wearing bright colors? On a white guy this outfit would be too preppy for my tastes, but this guy's interpretation of color, proportion and attitude makes me a fan of the whole package. Madison Avenue, NYC, October 2007.

This guy does a whole other thing with red pants--to equally strong effect. Williamsburg, Brooklyn, June 2007.

British-born painter David Hockney in his trademark mismatched shoes. The guy behind him in red pants looks great too. 1980. (Getty Images)

This guy has a good combination going on--the colors are bright but they're not screaming at me. Also, I've been noticing men wearing their ties shorter and shorter recently. What's that about? I'm not complaining. Spring Street, NY, October 2007.

The amazingly stylish sixties and seventies supermodel Twiggy is followed here by her equally stylish manager and then-boyfriend Justin De Villeneuve. He manages to suggest a Nantucket tradition in a laid-back, not-taking-it-so-seriously way. 1970. (Getty Images)

Sometimes wearing a less obvious color, like the tangerine linen shirt my stepfather, Will, is wearing here, works to great effect. Wainscott, NY, October 2007.

I'm not suggesting that you make like James Brown and wear a pink shiny cape--but I do like the example of how great adding a flash of color can be. 1969. (Getty Images)

 I would never have thought this guy's look was remarkable without the green pocket square. Broadway, NY, October 2007.

Douglas Fairbanks, Jr., looking great in not one but two loud colors. It helps that the blue shirt matches his eyes. 1967. (Getty Images)

I have to admit to you that this guy had knee socks on below his cut-off green shorts. I'm just pretending I didn't see them because this part of him looks great. Brooklyn, NY, October 2007.

If I momentarily suspend my attraction to Neil Armstrong's good looks and awesome feats, I notice how much I like the simplicity of his red cap.  Houston, Texas 1969. (Getty Images)

British society photographer Patrick Lichfield looks contemporary in this picture. I would never have thought a man could pull off a lavender shirt with yellow pants. But he does. That's the amazing thing about having your own style--when you believe in it you can do things that no one else can.  Port Ercole, 1968.  (Getty Images)