Raincoat: one rule for dry, stylish autumn outfits

Autumn doesn't ask permission. Your raincoat decides whether the rest of your outfit comes into its own, so this week we're looking at the long raincoat with hood, the light raincoat with drawstring, the men's field jacket with a waist cord, the short trench coat and the quilted coat with belt.

Underneath, nothing complicated: a roll-neck jumper, wide trousers or jeans, and boots or loafers with a thick sole. One rule holds it all together; you'll find it below.

The rule: choose the length first, keep everything underneath calm

Choose your coat based on how much it needs to cover, and keep what's underneath calm, dry and in one or two colours.

Length is the only real choice. A raincoat down to the knee keeps the rain off your thighs and the back of your trousers, and you'll notice it when you walk or cycle. A hip-length coat gives your arms more room, moves more easily and sits better under a bag strap, but then your trousers are left in the rain.

Once the length is settled, everything under the coat becomes calm: one jumper, one pair of trousers, one pair of shoes with grip. Autumn outfits go wrong when three eye-catching pieces fight each other under one shiny coat. Save the drama for the colour of your coat, or leave it out altogether.

Long raincoat for women: the hooded coat that covers your legs

This is the oversized long raincoat with hood and large pockets. It's water-resistant and light, so on a dry afternoon you can fold it up small.

Wear it open over a cream oversized roll-neck jumper and black wide trousers to work, closed over light blue flared jeans and brown mid-calf leather boots at the weekend, or with the hood up, a light pink cable-knit roll-neck jumper and black chunky loafers on a grey Tuesday.

The cut is roomy over the shoulders, and that's exactly the point: a thick jumper fits underneath without pulling at the sleeve seams, and on most people the coat falls to below the knee.

You'll find it with the other raincoats in the women's jackets.

Raincoat with drawstring: a waist instead of a tent

The light raincoat with hood has a large collar and a drawstring at the waist. This is the coat you reach for when you want a waist instead of a tent.

Wear it loosely over a grey jumper and light blue flared jeans, pull the cord tight over a black knitted set of jumper and mini skirt with navy blue suede ankle boots, or leave it open over black wide trousers and white trainers with a platform sole.

Colour detail: olive green looks warmer than a black raincoat and shows splashes less than white.

Compare it with the longer styles in the women's jackets.

Raincoat for men: the M65 field jacket with waist cord

For men, the M65 field jacket is the workhorse: a stand-up collar, four flap pockets and a cord at the waist, so the wind doesn't get in at the bottom. It's hip-length, so it moves well on the bike and under a backpack.

Wear it over light blue baggy jeans with a cord and brown leather trainers on a day off, with light brown wide trousers with pleats and black derby shoes when things need to look a bit smarter, or over a black jumper with khaki cord trousers when you're dropping the kids off at school.

Fit detail: only pull the waist cord until the coat stops flapping. Pull it too tight and a field jacket bulges at the hips.

You'll find it with the men's jackets.

Short trench coat for men: a smart raincoat for the office

The short single-breasted trench coat is the smart side of the same story. It buttons up to the collar, stops at the hip and looks like a coat rather than outdoor clothing, which is why it's worn over a shirt or a blazer.

Try it over navy blue pleated trousers and black derby shoes, over a black blazer for a night out, or with dark grey loose-fitting jeans and beige tasselled loafers at the weekend.

Colour detail: grey shows fewer water marks after a rain shower than black, so it looks fresher on the third wet day in a row.

You'll find it with the men's jackets.

Quilted coat for women with belt: for cold days between the showers

Not every wet week calls for rubber. The quilted coat with belt, often with a floral print, is the warm layer for the cold, drizzly, mostly dry day. Button fastening, stand-up collar, patch pockets, oversized cut.

Wear it over a cream roll-neck jumper and black wide trousers, with light blue denim dungarees and white trainers, or over a knitted two-piece set with black Mary Janes.

Fit detail: thanks to the oversized cut you can close the belt at the waist and still fit a jumper underneath, so you don't need to size up.

You'll find it next to the raincoats in the women's jackets.

What do you wear under a raincoat?

First, the jumper. A cream oversized roll-neck jumper or a light pink cable-knit roll-neck jumper fills the neckline of a raincoat and stops the hood sitting on your bare skin. A white cable-knit jumper with a short zip is the flatter choice under a trench coat because the zip sits neatly under a buttoned-up collar. You'll find them all in the women's knitwear.

Then the trousers. Black wide, high-waisted trousers with a front seam keep a long line under a long coat, and light blue flared jeans work under a hip-length coat because the coat's hem doesn't fall over the widest part of your leg. Have a look among the trousers.

Finally, the shoes, because that's where you win or lose a wet day: brown mid-calf leather boots with a folded edge, navy blue suede ankle boots with a low block heel, or black chunky loafers and platform loafers with a chunky tread sole that keeps you just above the puddles. Pick a pair from the shoes.

Colour: khaki, black and one coat that does the talking

With three colours you can handle almost anything. Khaki and beige go effortlessly with cream jumpers, brown boots and blue denim, and that's what most people already have in their wardrobe. Black is the answer for the city: it goes with black trousers, black loafers and a grey jumper, and never looks accidental. Olive green is the compromise, warm enough for autumn outfits and dark enough to hide splashes from the road.

After that, treat yourself to one coat with a voice of its own: a raincoat in a bold colour, or the quilted coat with floral print. The rule for that is simple. If the coat has a print, the rest is one plain colour, ideally cream, black or denim blue.

If you'd rather keep the colour off your coat entirely, put it in the jumper underneath instead: a light pink cable-knit roll-neck jumper or a dark red light jumper does the same thing and looks beautiful when the coat hangs open.

Fit, care and the most common mistakes

Buying a raincoat in your exact size without a jumper. Try it on over the thickest jumper you own. If the shoulders feel tight or the sleeves ride up when you reach forward, size up. Oversized raincoats are deliberately designed to be roomy.

Pulling the cord as tight as possible. A field jacket or a raincoat with a drawstring should skim your waist, not cinch it in. Only pull it until the hem stops flapping in the wind.

Hanging a wet coat over the radiator. Heat is the enemy of a water-resistant layer. Shake the coat out, hang it at room temperature on a wide hanger with the hood open, and let it dry slowly.

Wearing suede on a wet day. Save suede ankle boots and suede loafers for dry mornings, and choose leather boots or a rubber-soled loafer for real rain.

Letting the hood do nothing. A hood lying flat on your back collects water. Put it up, or choose a coat with a stand-up collar, like the short trench coat or the field jacket.

If you're starting from scratch, buy in this order: the long hooded raincoat for women or the M65 field jacket for men, then an oversized roll-neck jumper, then high-waisted wide trousers, and then mid-calf leather boots. That's four pieces, one rule and a week of dry, put-together autumn outfits. Start in the jackets collection.