Ever heard of the onion method? It’s the best way to stay warm in cold conditions and consists of carefully layering up, allium-style, in order to trap your body heat and stay cosy even in freezing temperatures. A smart layering system consists of a good base layer worn next to the skin, a waterproof and windproof jacket on top and between them the hero piece, a great mid layer. Fleeces and down jackets make the best insulation layers to keep you warm whether you’re hiking in the mountains or skiing through snowstorms, and we’ve included the best of both in our roundup.

Fleeces are made from synthetic insulated fabrics and are highly breathable, machine-washable, and quick drying.

Down jackets are a bit of a new kid on the outdoor clothing block, and can be stuffed with animal down or synthetic down. Synthetic is lighter, but can feel bulkier, while animal down is seriously warm but doesn’t offer as effective insulation when wet. It’s best avoiding very cheap animal down jackets, as the down is often unethically harvested from ducks and geese. Choosing a synthetic filling avoids that problem, although some companies such as Patagonia use humane, traceable down.

Mid layers aren’t usually waterproof – wear them alone on clear, cold days and pop them underneath a waterproof shell when venturing out in rain and snow.

Key features to look out for? We like mid layers with pockets and hoods. If you’re layering up for hiking, snow sports or other high-intensity activities, pick a breathable, lightweight mid layer. For early morning dog walks or winter camping trips, go for something heavier and bulkier that doubles up as a jacket.

1. Patagonia Nano Puff Down Jacket: £153, Patagonia

The ever-popular Nano Puff is a lovely bit of kit. Stuffed with water-repellent PrimaLoft synthetic down, it performs as well as animal down on the warmth front but retains body heat very well when damp. The durable Puff fits beautifully and packs down into its own jacket pocket, making it ideal for hiking, climbing and heading for the backcountry. Comes in 12 colours.

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2. Mountain Hardwear Ghost Whisperer Down Jacket: £250, Cotswold Outdoor

It may be a spendy one, but boy do you get a lot for your money when you drop it on the Ghost Whisperer. This multiple award-winning jacket claims to be the world’s lightest hooded down jacket, at under 250g. Its synthetic down filling wicks away sweat excellently and feels fantastic to wear - like slipping into a cosy duvet. It’s a fabulous all-rounder and worth investing in.

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3. Columbia Powder Lite Down Jacket: £85, Columbia Sportswear

A slim-fitting and versatile synthetic down jacket ideal for frosty autumn mornings and winter wear in the city. The outer shell is fully waterproof and the inner lining uses reflective tech to trap body head and keep you toasty. We also liked the well-designed high collar, elastic cuffs and zipped pockets. A hooded version is also available and it comes in work-friendly black, as well as blue and red colour options.

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4. Sherpa Nangpala Hooded Down Jacket: £240, Sherpa

Designed to keep you snug even if you’re out trekking on its namesake, the Nangpa La glacial pass in the Khumbu. Sherpa’s smart down jacket is stuffed with a mix of goose down and synthetic PrimaLoft down, so you get the best of both. The tough, water resistant outer layer is available in five nature-inspired colours.

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5. Protest Tolsona Fleece Jacket: £59.99, Protest

If you’re not usually a fan of the plain, slightly anorak-y look of fleece layers you might yet be converted by this gorgeous shirt-style jacket from surf and skate clothing brand Protest. We love the plaid print, faux-sheepskin collar, longer-length cut and popper fastening – this is an easy, cosy layer to sling on under a waterproof coat or for a spot of après-ski. Comes in blue and red.

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6. Quechua X-Light Down Jacket: £29.99, Decathlon

This is a bargain price for a very well-performing down jacket. Quechua’s X-Light is an attractive and functional mid layer for a smidge under £30, and sports a hood, well-placed pockets and a water resistant outer layer. Something’s got to give, though – while the sleeves and hood are filled with synthetic down, the body is filled with duck down and there’s no information online on how it’s sourced. Comes in six shades.

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7. Finisterre Incus Down Gilet: £95, Finnisterre

Shed the sleeves for more versatility and less weight in your pack with this super-flattering gilet, which packs up into its own pocket. The Incus is filled with a warm synthetic down and the outer is a durable rip-stop shell made from recycled materials. We favour the smart black but a neon-bright pink is available too.

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8. Picture Organic Clothing Basement Plush Hoodie: £102, Addicted

This crayon-bright hoodie is where skate style meets outdoor gear. Warm and planet-friendly, Picture’s Basement Plus is made with 70 per cent organic cotton and 30 per cent recycled polyester and features the cosiest, fluffiest hood ever – a great warm layer to stick under a thick jacket for snowboarding and winter travelling, or just for a bright bit of comfort on miserable rainy days.

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9. Fjallraven Ovik Fleece Hoodie: £130, Cotswold Outdoor

Fjallraven’s Ovik is here to give the humble hoodie a seriously smart makeover. This luxe fleece jacket, made with recycled polyester, has a cuddly brushed inside and a gorgeous knitted finish and is as well-made and warm as the rest of Fjallraven’s Swedish-designed clothing range. Be warned – buy the Ovik and you might not take it off all winter.

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10. Odlo Snowbird Mid Layer: £70, Odlo

This thinner mid layer is designed with winter sports in mind and works well as a light mid layer or just as a base layer if you’re planning to work up a proper sweat. It’s fast-drying, wicks away moisture well and doesn’t feel restrictive – a good choice for winter cycling and climbing. Also available as a pullover and comes in four colours.

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11. Mountain Warehouse Featherweight Down Jacket: £59.99, Mountain Warehouse

A good mid-priced mid layer, Mountain Warehouse’s Featherweight doesn’t overcomplicate things – this handsome jewel-green down jacket is extremely warm, water-resistant and well-cut, sitting nicely under a waterproof. If you’re after a jacket that doubles as an outer layer on crisp cold days we also rate Mountain Warehouse’s Peak padded jacket, £99 – it’s more expensive but for an extra £40 you get ethical synthetic down.

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The Verdict: Women’s mid layers

Figure out what you’ll be layering up for and then choose from our 11 quality contenders accordingly. The Patagonia Nano Puff and Mountain Hardwear Ghost Whisperer stand out as great-quality, ethical down jackets that’ll last you for years of winter adventuring. After something more casual? We love Protest’s plaid jacket and Picture’s cheerful hoodies. And for a well-priced all-rounder pick a down jacket from Mountain Warehouse’s smart, nicely fitting options.

Sian Anna Lewis is a travel and outdoors writer and editor of The Girl Outdoors blog

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