Your definitive guide to that age-old conundrum: deciding how to dress when the weather is decidedly… indecisive.

Allow us to induct you, dear reader, into the world of “transitional dressing”. It’s not a phrase we use very often – and especially not now, with gender issues at the forefront of the public imagination – but it’s an important weapon in your sartorial arsenal nonetheless.

In layman’s terms, it describes how you might dress for that in-between weather; not too warm and not too cold. In London, where MR PORTER’s headquarters are based, that description more or less accounts for most of the year, so trust us when we say that we know what we’re talking about here.

So, how to go about it? When dressing for weather that can’t seem to make up its mind, the best place to start is with a good medium-weight jacket. There’s never a single must-have jacket for spring, but a range of options to choose from instead. To help you sort the wheat from the chaff, we’ve picked out our favourites – and given you a few examples of how to wear them well.

What a perfect time to dust off the old cliché: if you don’t like the weather in spring, just wait a few minutes. When dressing for this most capricious of seasons, your buzzword is “adaptability”. Just combine a couple of easily removable layers, as the gentleman in the above photograph has done, and you’ll be ready come rain or shine. As for the layers themselves, while the dreaded “double denim” has been responsible for a few crimes of fashion over the years (see: Timberlake and Spears vs the US, 2001), above is an example of it being done properly. The denim jacket and shirt are of discernibly different washes, and the rest of the outfit – grey wool trousers and a plain white tee – are suitably subdued.

The coach jacket has been enjoying a bit of a comeback of late, possibly off the back of the 2015 N.W.A biopic Straight Outta Compton, which served as a reminder to all of us of just how dope Eazy-E and Dr Dre looked in Raiders gear. Its modern-day iteration retains the fundamental design details – press-stud placket, drawstring hem and a pointed collar – but is a little sleeker and more refined, and is probably best worn without the Compton snapback and gold chain. In this example, our man has paired his inky blue coach jacket with a pair of loosely cut trousers in a coordinating, darker shade of blue and some old-school Vans.

The souvenir jacket has its origins in post-war Japan. You’d have to strike eBay gold to find an original in good condition, but, failing that, you could always try one of the versions made by designers such as Saint Laurent, Valentino and Gucci this season. How to wear it, then? As with any “statement” piece, the best course of action is to keep the rest of your outfit understated. By opting for an all-black look – denim, sunglasses, and even bag – Mr Simone Marchetti, editor-in-chief of Italian Vanity Fair, above, has ensured that the embroidered details of his souvenir jacket shine all the brighter.

One of the utility jacket’s most famous protagonists is the legendary New York street-style photographer Mr Bill Cunningham. He prefers his in a bold shade of indigo blue, but we think it looks just as good in chino-beige (yes, we’ve just patented the name of that colour). Cut from hard-wearing twill cotton, it’s a utilitarian garment through and through – but by popping the collar and keeping everything but the top button unfastened, this man has managed to turn functional into fashionable. One piece of advice: don’t wear it with chinos. Not beige ones, anyway.

There’s a new breed of blazer on the block. Cut in the traditional fashion, but with polyester and nylon taking the place of cashmere or linen, it combines the fit and formality of a blazer with the lightweight, weather-proof qualities of the best modern sports gear. It’s a perfectly simple piece of clothing: just follow the lead of Mr Nick Sullivan, creative director at US Esquire, above, and wear it as you would a normal blazer. Dark denim works well to offset the satiny sheen of the blazer’s material, while a pocket square provides the look with a smart finishing touch.

We’ve compiled A Gentleman’s Guide To Suede before, so regular readers will already be aware of the many and varied ways in which this endlessly versatile material can be worn. This spring, it’s gossamer-thin, light as a feather and comes in a range of 1970s-inspired shades of caramel and brown. Our gent here is pictured in a tan bomber jacket so soft that it almost looks like a cardigan. He’s wearing it over a simple white tee with a pair of Ray-Ban Clubmasters, a retro Casio wristwatch and a determined Fashion Week stride.

We’ve waxed lyrical on the benefits of a good double-breasted blazer many times over the past few years. Not only does it have the effect of making a larger man look slimmer and a broad-shouldered man look like Superman in a suit, but it also makes any man, no matter his physique, appear infinitely more refined. It’s the perfect outer layer for spring, too, offering a little more insulation than a standard single-breasted blazer. And, as the example above illustrates, it needn’t be stuffy or overly formal. Just choose an unstructured, soft-shouldered jacket and wear it over an open-necked shirt.

This decidedly modern take on the M-65 army field jacket comes with the slightly pointless additional detail of bellows pockets fitted on the back. It’s the sort of detail that you might expect on a cycling jacket, and gives this strange hybrid a unique appearance. But what really catches the eye here aren’t the pockets but the excellent colour coordination of olive green, earthy tan and indigo blue. While we’re on the topic of colour, the first rule of wearing a field jacket is to avoid trousers in the same hue. That turns it into a safari suit, which makes you look like a dictator from the 1970s. The 1970s may be in, but they’re not that in.

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