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 love peacoats of all kinds -- the authentic naval version and upscale designer versions, long and short, navy and black, old and new. There are in fact so many versions today that it's sometimes hard to tell what actually constitutes a peacoat. My idea of one is a dark-colored coat that is military in feel and made of thick wool fabric. It also has to be above the knee and/or double-breasted. There is something about the formality of the tailoring and the stiffness of the fabric, mixed with the casual way that most men wear them today that make them very attractive to me. It's like when a guy who I'm used to seeing dressed-down puts on a suit, I think "Wow, he looks great dressed up!" The peacoat is an easy way to add a bit of "dressing up" to your everyday or weekend outfit. After all, I know I'm not the only girl who likes to see a guy in uniform.

This guy shows a lot of personal style by wearing the top buttons of his peacoat closed but parting it in the front to put his hands in his pockets. His pose is functional and unaffected but looks cunning nonetheless. East 60th Street, NYC, February 2008.

I do know men who can carry off wearing a fur coat. My stepfather, for instance, has a coyote parka that he wears at his house in the Adirondacks. I also have a more scruffy friend in his thirties who looks utterly convincing in a vintage beaver overcoat. But beyond that it's challenging for me to think of many cases where men pull off wearing an abundance of fur. However a bit of fur, most popularly a fur collar, is a different story. There are tons of options--a bomber jacket with a shearling collar, a down parka with a raccoon collar, or an overcoat with Persian lamb collar being among my favorites. And while an uptown man looks great wearing a fur-trimmed winter coat with a polished business look, I tend to think downtown guys look better if they dress down their fur with jeans and sneakers for a younger, more laid-back look.

This is a fantastic coat. I've never seen one like it. I like everything about it--the color, the fit, the combination of materials. Also, it's hard to pinpoint--it could be from the army-navy or from a very expensive designer. West 13th Street, NYC, January 2008.

The great thing about tweed is that it lends an air of traditional good taste to any look -- so much so that you can afford to mix it up a bit, add some irony, or try something new without risking too much. I've seen guys using tweed as a foil to a ridiculously bright colored shirt, crazy rock star hair, or just as a way to give a bit of dignity to downtown grunge. If it weren't for the reliably classic effect of tweed, I'm pretty sure I would have just passed them by, but I didn't -- I stopped and took a second glance. Even Albert Einstein, with his droopy face and mad scientist hair, has the look of a gentleman in his tweed coat.

There as so much that is both uptown (tweed jacket, colored sweater over the shoulders) and downtown (knit hat, graffiti) about this guy. It's a good mix. Mercer Street, NYC, February 2008.

As you've probably noticed, I have a thing for guys in military clothes, and bomber jackets are no exception. Maybe it's a holdover from a Top Gun obsession in my teenage years, or just that uniform thing I've talked about before. Regardless of whether you look like Tom Cruise--or not!--men look great in all incarnations of the bomber jacket--from the most authentic version worn by the Alaskan Air Force during World War II to edgy downtown reinterpretations created by forward-thinking designers. There are also lots of fabrics nowadays for grounded wingmen to choose from. While I am personally most partial to the teal nylon Army-Navy version with a fur collar, or the straight-out-of-the-war-photo shearling version, I do in fact like most kinds I've seen on the street and online, including Axl Rose's leather version (complete with Guns N' Roses logo) from the nineties.

I like this down puffer / bomber jacket combo - it's a sporty, but warm, look for winter. Noho, NY, January 2008.

Double-breasted coats and jackets don't have to look as country club formal as you might assume. Of course, if you choose to wear a navy blazer with brass buttons, you might have to work extra hard to add a playful dose of irony to its conventional aura--or maybe sometimes it's a relief to leave well enough alone. But in most cases, the traditional connotations can be overridden with new shapes, contrasting references, and a healthy sense of your own style. I often see my friend the designer Phillip Lim looking thoroughly modern in traditionally cut double-breasted blazers in fire engine red or cobalt blue, while Prince Harry boldly reinforces the old-school style of his double-breasted suit jackets by tossing a bowler hat into the mix. Perhaps most imaginative of all, though, is Andy Warhol, who threw a black leather motorcycle jacket over a classically cut black double-breasted blazer. But then again who was better than Andy Warhol at mixing references and identifying icons?

Phillip Lim, (pictured with Anna Wintour), looks entirely contemporary in his boxy blue double-breasted blazer. 3.1 Phillip Lim store opening, NYC, July 2007.

I always think of a men's overcoat as a particularly grown-up item of clothing. I remember when I was 15 I went to Antique Boutique on Fifty-ninth Street in New York to buy a vintage men's black overcoat for myself. Even the smallest size was too big on me, but I didn't care--I just desperately wanted to look like Molly Ringwald at the end of The Breakfast Club with Judd Nelson's overcoat draped over her shoulders. I grew up at least two years in an instant just by walking around in that coat. I also remember my father telling me that when he was 14, he would put on his father's overcoat, perch himself on top of two firm pillows in the driver's seat of his father's car, and illegally drive around Palm Beach at night when his parents were out at cocktail parties.

Regardless of the mature, upstanding image of the tailored overcoat, there are many new versions today, or just new ways of wearing them, that make me look at them in a different context. I've noticed more than a few men wearing sporty outerwear--such as a down vest or windbreaker--under their overcoats. I happen to really like this look. There is an Italian outerwear company called Fay (sold at Barneys) that stitches a cashmere cardigan or down vest "dickey" inside the lapel of the overcoat so it's actually all one piece. Clever. I've also seen pea coats and duffle coats that have been morphed into longer, more structured version of themselves. But perhaps the most inventive overcoat design I've seen is the Inverness cape made by Harris Tweed (an old-school English tailor) in 1947--it was a belted tweed overcoat with sleeves that could be unzipped up the side to turn the coat into a cape. Sounds suspect I know--but it looks cool to me. See for yourself below.

I like the shorter length of my friend Stewart Shining's overcoat. I also love his chunky cardigan worn underneath--it's a great contrast to the formality of the coat. Bleecker Street, NYC, December 2007.

I don't own a raincoat for two reasons: First of all, I usually make due with the biggest umbrella I can find, and secondly, there are several dozen options in my husband Christopher's closet that are just better than anything made for women. It's mostly on the weekends when I feel free to grab one of my husband's 17 raincoats, and I know he likes how I look in his loose red Patagonia slicker. He has all these options because, frankly, he can't be bothered with umbrellas and, even if he could be, he'd lose one the first place he put it down. Furthermore, he rides his mountain bike around the city no matter the weather and keeps himself fully covered--he even has rain pants and rain hats!

Christopher's raingear is on the casual end of the spectrum, whether it be military-inspired or just a plain and simple slicker. But in my travels uptown, I kept checking out business men who want to, have to, aspire to look put-together when they go to work. I sympathize entirely: They can't throw a standard-issue anorak over a custom-tailored suit, so they opt for classic shapes--double-breasted trench coats, James Bond–style overcoats--but in technologically updated waterproof fabrics. Nothing seemed overly designed or too tech-y, everything was formal and functional. Now if I could just find one in my size.

When I think of men's raincoats this is the kind of coat that pops up first in my head. I'll bet it was made by London Fog. 1986. (Credit: Getty)

This guy's coat is the here-and-now version of Reagan's classic overcoat. You can't get more basic--in a good way--than this. Lower Fifth Avenue, NY, September 2007.

Was Edward R. Murrow born in this look? I feel like he's wearing the same thing in every picture I see of him. Clearly it worked for him, wherever he went. In this instance, he was in England to cover WWII for CBS Radio network. London, 1941. (Credit: Getty)

Does anyone know who this guy is? He looks so familiar to me. I feel like he runs an art museum or something. Nevertheless he has a great sense of style and proportion. Also did you clock the uptown beard? Madison Avenue and 61st Street, NY, October 2007.

American business man Harold Vanderbilt standing in the rain with his wife. My heart rate speeds up when I look at this picture. It's that good for me. 1935. (Credit: Getty)

A technical version of a trench. Very James Bond. Park Avenue, NY, October 2007.

Captain Mark Phillips, Olympic gold medal-winning horseman and former husband of Princess Anne of Britain, wears a traditional English sporting raincoat. You should know by now that I'm a sucker for any '70s photo of the British Royal family. 1978. (Credit: Corbis)

My husband Christopher, in a matching rain slicker and hat, walks our daughter Coco around the sequence of jumps at a horse show in England. She came in third. Heythrop Pony Club, Moreton-in-the-Marsh, England, June 2007.

Although I like the look of this coat, I would say it's good for drizzle at best. Union Square, NY, September 2007.

I can't tell you how many pictures I found of men who, like me, walk around in the pouring rain with an umbrella, but no waterproof coat. Stan Smith, Wimbledon, 1972.(Credit: Corbis)

I love the idea of a trench "jacket." Madison Avenue, NY, October 2007.

Eric Shipton, a Sri Lanka–born British mountain climber and explorer, stands with a Chilean glaciologist in their all-weather gear. Eric Shipton is hot--the fact that he's an explorer, his clothes, the way he's standing--it all works for me. Tiera del Fuego, Chile, 1962. (Credit: Getty)

This blog wouldn't be mine without a groovy Brooklyn dude thrown into the mix; and his military-inspired raincoat with the double-breasted "lip" is fantastic. Bedford Avenue, Brooklyn, September 2007.

This is what I call a dressed up casual look. He's wearing jeans, there's no tie; but the overall look is very pulled-together, raincoat and all. East 59th Street, NY, October 2007.

I can't really tell what these Haitian men are wearing. Are the coats always so shiny? Or are they just wet? Did the guy on the left drape a detached hood over his head? All I can tell you is that I really like the overall effect. 1974. (Credit: Getty)

I love a poncho--and I'm sure you know this but you have to be pretty tall to carry one off. Woodstock, 1969. (Credit: Corbis)

Some more contemporary poncho-wearers in Beijing rush hour traffic. Do you think purple is a standard-issue poncho color in China? I hope so. 1993. (Credit: Getty)

Sugar Ray Robinson stands outside Madison Square Garden during a rain delay of his match against Joey Maxim. Maxim defeated Robinson for the light heavyweight championship two days later. 1952. (Credit: Getty)