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Castelli Cycling Rain Jacket Guide

By Stan Portus –  30 December 2020

What is the best rain jacket for cycling? From staying dry inside your jacket while pushing hard on the pedals to wanting something to protect you throughout your bike packing trip, there is a myriad of options. Read our guide to find the best jacket for you.

A cycling rain jacket is one of the best ways to stay comfortable out on the bike. This is because getting wet often leads to getting cold, even in mild condition, so staying dry is a top priority whether you’re out training regardless of the weather, bike packing, or commuting to work every day.

Cycling comes with its own specific demands on wet weather gear. Due to how your body is working while on the bike you are going to be generating your own heat and moisture from perspiration. A totally waterproof jacket is going to create a “boil-in-the-bag” feeling where although no water is getting in, no moisture or heat is getting out either. The effect of this isn’t just overheating and feeling claggy while moving, but it can be unpleasant when you stop too. Five minutes stationary on the roadside and that built up moisture will make your body temperature drop.

Consequently, breathability is as important as waterproofness. Many cycling jackets use waterproof and breathable membranes which have pores which are so small that water vapour can escape but liquids can’t get in. The industry leaders in this are GORE-TEX which is used across Castelli’s range of jackets.

Membranes work exceptionally well as they are ultra-thin meaning the moisture has less material to pass through and are consequently more breathable as well as being lighter.

GORE-TEX SHAKEDRY™ fabric is the industry leader. This material does away with the usual construction of membrane fabrics leaving just a 2-layer reinforced membrane to offer the very best breathability. However, the compromise here is durability so we suggest using SHAKEDRY™ if you’re road riding and choosing a more robust material if you’re gravel riding.

3-layer GORE-TEX jackets offer better durability making them a great shout for gravel riding or bike packing. Jackets that use PU (polyurethane) coatings are also great for off road riding and touring as the PU offers an excellent DWR as well as being durable. PU Coatings can also be paired with stretch fabrics making them great for when comfort is a top priority.

Regardless of the material used in the rain jacket body, taped seams are also essential to eliminate any points where rain or road spray could get it. Waterproof zippers, like the ones used on Castelli, also help seal the jacket completely.

The other demand cycling makes on rain jackets is packability. Cycling rain jackets need to be compact enough to fit in a jersey pocket or frame bag. Again, thin membrane jackets are an advantage here as they pack down small, but there are other options too. Emergency rain jackets are designed to major on packability and durability and are often made from less expensive fabric which provide the minimum levels of waterproofing you will need out on the bike.

Take a look below to see our pick of Castelli rain jackets to keep you riding through even the wettest conditions.  

Castelli Gavia Jacket:
The most effective barrier against the elements

The Castelli Gavia Jacket is for those days when having the most effective barrier against the rain and cold is the top priority. If you’ve never had a jacket like this, you’ve never experienced going out because you must and then having one of the most epic days ever.

Photo of a cyclist looking at the camera semi side on wearing the Castelli Gavia Rain Jacket speckled in mud

For the Gavia, Castelli has chosen a 3-layer mid-weight GORE-TEX fabric for the main body and sleeves. The slight weight penalty of the fabric over more race orientated fabrics repays itself by providing greater durability and complete protection from the wind and rain. The cut is slightly more generous than race kit too for riding in conditions when comfort is essential.

Stretch GORE-TEX in the shoulders and wrists make for easy on and off and greater freedom of movement than other shell jackets so you can get into a more aggressive position when the riding demands it. Stretch side panels also help improve fit and mean loaded jersey pockets can be accommodated under the jacket.

Even though it is for the most extreme conditions, the Gavia can still fold up small to fit into a jersey pocket, or more likely a frame bag, as this jacket is just the thing for multi-day adventures. 

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Castelli Gavia Jacket

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Castelli Goccia Jacket:
A rain jacket with an aero advantage

The Goccia Jacket from Castelli is a pared back design that focuses on doing three things superbly: it is fully waterproof, the four-way stretch provides ultimate comfort regardless of body shape, and it provides an aerodynamic advantage even in the wet.

Studio photo of a model wearing the Castelli Goccia Jacket shot straight on.

At the core of the jacket is the Tempesta Stretch fabric, which gives the Goccia its rain protection and stretch fit, as well as making it durable and packable enough to fit in a jersey pocket. The fabric has a windproof PU membrane that provides 10,000mm waterproofness, as well as first-class breathability for warmer temperatures or when your body is working harder.

Taped shoulder seams prevent water entering the jacket at one of the most exposed points, and a covered YKK® Vislon® zipper stops water getting in on the front. An extended tail provides protection from wheel spray.

Designed to be worn over a jersey, the shell jacket has foregone rear pockets to keep the construction simple and reduce seams. 

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Castelli Goccia Jacket

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Castelli Idro Pro 2:
For going out no matter what

The Idro Pro 2 is a light, packable, highly breathable, durably waterproof and aero fitting wet weather jacket. It is ideal for riders who never say no to riding and for whom a rain jacket is an essential piece of kit.

Close up photo focussed on the shoulders of a cyclist wearing the Castelli Idro Pro 2 Jacket.


The Idro Pro 2 uses GORE-TEX SHAKEDRY™ fabric in the body for the best breathability, and Gore’s Topo stretch fabric inserts in the elbows, shoulders and side panels. The Topo fabric means Castelli can cut the SHAKEDRY™ panels to create a much more aero design than other jackets made from this material while still ensuring unencumbered movement.

Castelli has given the Idro Pro 2 two external pockets, so you don’t have to unzip to reach for a gel or bar. It also has a long tail to shield you from the spray coming off your back wheel. They've also given it a soft neck liner and reflectivity detailing for safety. 

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Castelli Idro Pro 2 Jacket

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Castelli Idro 2: 
Super lightweight GORE-TEX® protection

The Idro 2 is the smallest, lightest, fully waterproof and breathable GORE-TEX jacket available from Castelli.

This jacket will change the way you dress and pack for a ride. And you’ll be extending your rides into conditions when rain is in the forecast because you know you’ll be perfectly covered. Packing up smaller than most gilets this jacket will mean you never need risk a cold descent or heavy rain again.

Female cyclist riding up a hill wearing the Castelli Idro 2 jacket. In the foreground is long grass in soft focus.

The Idro 2 uses GORE-TEX SHAKEDRY™ fabric. This material does away with the usual construction of membrane fabrics leaving just a reinforced membrane. The jacket is cut to be a race fit with an extended tail, avoiding the flap that some GORE-TEX® cycling waterproofs have and providing protection from wheel spray.

The Castelli Idro 2 was included in Cycling Weekly’s 2020 Editor’s Choice, a roundup of the very best cycling equipment:

“Superlative performance in a tiny package. There's nothing not to like about the Castelli Idro 2 jacket, great fit and almost perfect on the bike performance. There are few to beat it.” 

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Castelli Idro 2 Jacket

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Castelli Idro Women's Jacket

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Castelli Emergency Rain Jacket:
Packable Protection

The Castelli Emergency Rain Jacket the perfect garment to sit in your back pocket just in case the weather takes a turn for the worse.

Castelli has made this jacket to be completely waterproof and it's reasonably compact too making it easy to stash in a pocket. As you’d expect from Castelli it has an amazing on-bike fit, yet it’s still roomy enough to fit over a Gabba.

The Emergency Rain Jacket features rain gutters on the arms and on the back to channel the worst of the weather away from your hands and bum. It also features the Castelli Z line collar for increased comfort around the neck and as you would expect from a fully waterproof jacket, a waterproof zip and seam sealing.

Although it isn’t designed for all-day rain protection, the Emergency Rain Jacket still offers great protection. The Deluge Light 2.5-layer waterproof fabric keeps the rain off with 10,000mm water column.  

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Castelli Emergency Rain Jacket

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Castelli-Castelli Women's Emergency Rain Jacket-Yellow Fluo-XS-CS175380321-saddleback-elite-performance-cycling

Castelli Women's Emergency Rain Jacket

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