Castelli Alpha RoS 2 Light Women’s Jacket

The Castelli Alpha RoS 2 Light Women's Jacket is a high quality, high performance and comfortable three-season option that puts a significant dent in your wallet. It does do away with gilets or numerous baselayers though – it protects brilliantly in a wide range of temperatures and weathers.

There are so many winter jackets available these days the choice is overwhelming. Castelli alone has no fewer than seven long-sleeved jackets on its site, but I'd say the Alpha RoS 2 Light is the best 'all-rounder' option there. It works hard from early autumn through to spring, and needs very few additional bits of kit to support it.

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The Alpha RoS 2 Light has a double layer build. Inside is the lightweight, insulating fabric known as ProSecco Strada. Outside, the front panels and sleeve fronts are made of Gore-Tex Infinium Windstopper 150, while the back and underarms are Nano Flex Xtra Dry for protection against rain.

Each layer has its own YKK zip – it looks a bit like you've got half a waistcoat sewn into the jacket. It's a strange idea to get used to; the rote action of jacket-on-jacket-off goes out the window.

Fit

Of the three Castelli jackets/jerseys I've been testing recently, this is by far the best fit for me. The cut is well thought out and, despite this being a winter jacket, it doesn't have that sense bulk or thickness you so often find.

In my size it gives a relaxed fit with a little room round the torso and down the full length of the sleeves (it's not me in the photos), which seems to promote ventilation and moisture transfer. While being generous, the cut is flatteringly feminine and the jacket doesn't budge or flap in any riding position. Consider sizing down if you like a very snug fit, though.

Sleeve and body length are both good. The cuffs are simple elastic affairs, and sit over a slim glove perfectly – bulkier winter gloves are happier over the top.

The wide, raw-edge elasticated waist is brilliantly designed, coming into its own when you're on the bike. It sits low at the front and has generous length at the rear. It simply doesn't budge; the elastic, coupled with a silicone strip, effectively forms a seal between the jacket and your tights/shorts. Despite the relaxed fit, I never once found it needed adjusting.

The neck line is high – perfect for really cold days – and warm enough you'll want it unzipped on mild days. There's a tongue of soft fleecy fabric that sits against the back of the neck, too. As a whole, the fit is engineered to keep the cold out and the heat in, and it does that very well.

Performance

Castelli recommends this for between 8-15°C. While I haven't had the opportunity to take it up to 15 degrees, I've had plenty of rides from around 12° to below the lower limit.

While I'm not a fan of no baselayer (in any weather), the Alpha RoS 2 Light easily functions without one on mild days; the torso is soft and comfortable against bare skin, although the sleeves are not so luxurious. Once the mercury hits single figures, a long-sleeved base layer was all I needed beneath. I found with this set-up I was comfortable down to near-zero. The jacket keeps off bitter wind chills brilliantly.

Castelli doesn't guarantee 100% waterproofing, but in light rain and showers the water beads off, the shoulder seams are sealed and the zip is waterproof. The Nano Flex Xtra Dry fabric on the back holds off showers too, but after 30 minutes of heavy rain it begins to feel damp (yet not cold).

I never sensed a build-up of moisture and have to admit to being surprised that, when took the jacket off after some pacier rides, there was significant moisture clinging to the jacket's interior... Still, the fabrics perform sufficiently well to keep me warm despite the build-up.

Practicalities

The three rear pockets are perfectly positioned for access on the move and generous in size, while a base insert means you can stuff them full and the pocket stretches – not the jacket. There's a fourth zipped pocket at the side for keys or money. For me, this is so much more accessible and functional than one sitting on top of another pocket.

I absolutely love this Fiery Red – top marks for visibility – but if you prefer more subtle colours it also comes in Rescue Blue, Savile Blue and – fantastically – Light Black.

The only thing missing from the Alpha RoS is a lower zip guard. Castelli's own tights have paid the price for this omission by bobbling up, though less delicate fabrics haven't been affected.

> 29 of the best winter cycling jackets - stay warm and dry when it's cold and wet

Quality and performance come at a cost, and the Alpha RoS 2 Light is no exception. It's still not the most expensive, though – Rapha's women's Classic Winter Gore-Tex Jacket will set you back a further £45, while Assos' UMA GT Ultraz Winter Jacket EVO is £290.

More thrifty alternatives include dhb's Aeron Rain Defence Polartec Jacket for £130 or Lusso's Aqua Repel Jacket at £134.99; Stu tested the men's version earlier this year.

Overall

The Alpha RoS 2 Light is packed full of technology to keep you comfortable, warm and dry throughout a good chunk of the year. Yes, the price is high, but its versatility, quality and style are unquestionable.

Verdict

Superb jacket for most conditions and three full seasons