Castelli ‘Hot Weather’ Kit: Just when our man in Spain, Alastair Hamilton thought he had reviewed his final bike kit for the 2026 summer, Castelli sent him their A/C Collection for ‘Hot Weather’ cycling. We don’t hear him complaining about getting out on the bike in the sun.
Cool design and cool to wear
Alastair Hamilton PEZ sez: As the mercury is rising here on the east coast of Spain, it was a welcome surprise to receive an email from Castelli (thanks Harriet) suggesting it would be a good idea for me to try their new for ‘Hot Weather’ kit. In the Spring I reviewed the Castelli Espresso 2 Summer collection and thought it was great for hot days, but Castelli have gone one step further and released their A/C Collection for those very hot rides.
Ready for the hot weather
Climber’s A/C Jersey
Castelli call this a ‘climber’s’ jersey, but don’t worry those of us that gravity is unkind to can also look good as they suffer on a hot climb. The first thing I noticed with the A/C jersey was the design, not the usual one pastel colour that seems to be the fashion at the moment, but a deep purple (Castelli call it deep Bordeaux/white) with a smoky, lighter splash across the front and back. Subtle, but a great look.
Great design
The trick of keeping you cool in hot conditions comes down to the materials combined in the making of the jerseys (and shorts). The front and side panels have a very open weave, the rear is also like a mesh, but not as open, and the arms and shoulders have a slightly closer weave material and the sleeve edge has been laser cut. The neck doesn’t have a collar, but there is good sized hem. The full length zip has a flap on the inside at the top and flaps either side on the front of the zip, plus a great little Castelli scorpion on the tag. There are three rear pockets and the middle one is slightly wider than the outside two. There is no small zip pocket, which is a shame for a training jersey. The jersey is fairly short as is normal, but the pockets are still easily accessible.
Very cool!
The wide elastic waistband has rubberised ‘CASTELLI’ on the inside to hold it in place. All the seams and joints are double stitched and the nylon zip has wide tapes on the inside. The A/C jersey has ‘CASTELLI’ running down the front next to the zip, ‘ROSSO CORSA’ just above the pockets and a scorpion printed on the middle rear pocket. The Climber’s A/C jersey is available in four colours and seven sizes.
Lots of scorpions
A/C Bibshorts
Starting with the Progetto X2 Air Seamless seat pad, it’s the same as the one used in the Espresso 2 bib shorts that I reviewed in April. It’s also the same as the one used in the Espresso kit from 2025, but as they say: “If it ain’t broke, don’t fix it.” I’ll repeat what I said about the chamois in the Espresso 2 bibs: “The most important part of all cycling kit is the chamois/seat pad and the Castelli pad is really one of the best designed and made. The sit bones have the thickest padding (15) and the central section underneath has a little less (09). There is less around the edges with a little more at the front for the ‘family jewels’. When you first pull the bibs on, they do feel a bit bulky, but when sat on the saddle you just feel comfort.” I still feel the same way.
One of the best
The material used in the A/C bibs is the secret to keeping you cool. The bib is of a total mesh elastic cloth that only stretches one way. The straps are also nice and wide, with one piece at the middle of the spine. The top of the shorts has an elastic hem, except at the front where the material is doubled over. I presume this is to make it easier for a (gentleman’s) ‘comfort break’.
Comfortable and cool shorts
The shorts consist of six main panels and two leg bands. The outside panels are made of a more perforated material for coolness and breathability and Castelli claim that it still offers sun protection. The front and back sections are of a slightly thicker cloth, but still perforated. Don’t worry, you can’t see through them. The leg bands are also perforated and wide with a rubberised finish on the inside to keep them in place.
Wide straps
The tailored cut gives a nice feel and close fit to the shorts. Very comfortable. The logos are subtle; There is a small red Castelli scorpion on the back of the left leg and a ‘CASTELLI’ on the right leg just above the leg band. The A/C Bibshorts are available in Belgian Blue and Black and in seven different sizes.
Multi-panel shorts with breathable material
A/C 18 Unisex Sock
The A/C socks are available in black and white. Well, white is enough for me, but if you are feeling adventurous then go for the black. They also come in three sizes. I have to admit that I have started to come round to coloured socks, but still feel that white looks the best. My other confession, and this will please Chuck Peña (our sock guru), my socks have got a bit higher. From just over the ankle bone, they have ventured up to just under the calf muscles (Gastrocnemius). Anyway, back to the Castelli A/C 18 unisex socks.
Very white socks
Comfort is the No.1 thing with these socks. They are lightweight (51g) and fit very snugly, no wrinkles or folds inside your shoe to annoy you on a ride and they are left and right specific. Castelli use different materials in different areas. The toe, sole and heel has a smooth, slightly thicker cloth, the leg is ribbed running round the leg and the top of the foot is ribbed in different directions depending on the position. Castelli say the socks are best between temperature of 18°C and 40°C (64°F to 104°F), nice, as those are the temperatures I get here through the summer. The top of the sock has been doubled over to hold the leg in place. ‘CASTELLI’ is written around the back on the cuff and there is a red line across the toe, maybe a scorpion logo would have been nice, but they are cool and very comfortable.
A good fit
How does the kit feel out on the road?
How was it? Cool! The day I first tested out the Castelli A/C Hot Weather kit, the temperature was around 30ºC (86ºF), so not super hot, but warm enough. To be scientific I split the ride and wore a base layer for part of the time and just the Climber’s jersey for the rest of the time. This experiment didn’t prove much and I think you can wear either. I would say if the temperature is below 20ºC, I would wear the base layer.
With or without a base layer?
Okay, back to the ride. The pad/chamois is one of the best, I’ve said this before, so no complaint there. The shorts and jersey feel light, to the point of having to look down to make sure you’ve not gone out naked. The air does pass through the jersey and shorts to keep you cool, but you don’t feel the sweat going cold on the surface of your skin. Everything was comfortable, no annoying creases or folds. The leg and waist grippers held everything in place with out squeezing and the pockets didn’t pull the jersey down, even with a camera, iPhone, inner-tubes and a mini pump. The pockets are easily accessed without being a contortionist. The socks fit well in the shoes and didn’t fall down. What didn’t I like? The low collar and the lack of a small zip pocket. But the kit does what it is meant to do, it helps to keep your body temperature down and is very comfortable.
Yes I felt and looked cool! Well I thought so.
Cool…
Castelli sez:
Castelli Climber’s A/C Jersey – EU€120, US$155 and UK£125
Racing in the Alps in July is for a select few, but the products that come out of that experience are absolutely amazing for the rest of us. We made this jersey for hot days in the high mountains, based on direct feedback from the pros. They wanted a jersey to keep them cool on hot days without sacrificing aerodynamics. The Climber’s A/C Jersey features the same CFD-based seam construction as our Aero Race 8S Jersey, but we’ve used the most aerodynamic 3D mesh fabrics we could find for optimal cooling. These fabrics also have a great soft and stretchy quality to them, giving this jersey a comfortable fit, too, which you need for big days in the mountains. And since this jersey is meant to be used in the sun, we’ve also made sure the fabric on the back blocks 90% of UV rays.
Product Features:
- CFD-based fabric placement and seam construction
- Engineered rapid cooling, light weight, and aero efficiency
- Airflow shoulder construction
- Flusso 3D fabric on front
- StradaPro 3D back for breathability
- Elbow-length stretch sleeves with raw-cut edges
- Elastic around waist to keep jersey in place and support pockets
- YKK® Vislon® zipper
- UPF 13.
Castelli A/C Shorts – EU€160, US$190 and UK£170
Summers are getting hotter, and for those of us who need to ride at the hottest time of day, during our lunch breaks, we need kit that can help to keep us as cool as possible. The new A/C Bibshort was developed to allow the maximal amount of cooling and breathability while still offering protection from the sun. Everything about this short focuses on keeping you cool. The sides and leg grippers use a closed mesh for maximal airflow to help cool you and keep you dry. The bib straps are as minimal as possible while still functioning to hold the short in place. The Progetto X2 Air Seamless seat pad, while providing all-day comfort, dries quickly. Everything about the A/C Bibshort is designed with the one goal of keeping you cool and comfortable on the hottest days.
Product Features:
- Closed-knit mesh side panels for maximum breathability and sun protection
- Mesh leg grippers with integrated silicone
- Minimalist mesh bib straps
- Progetto X2 Air Seamless seat pad
- UPF 50+.
Castelli A/C 18 Unisex Sock – EU€20, US$22 and UK£20
The Castelli A/C 18 socks are designed to provide a feeling of freshness and lightness during summer rides. Perfectly suited to high temperatures, they combine comfort, breathability, and support to meet the needs of demanding cyclists.
Product Features:
- Ultralightweight construction for the hottest days
- Highly breathable and durable nylon threads
- Ribbed texture for the perfect mix of lightness and durability
- Castelli wordmark on cuff
- 95% poliammide, 5% elastan
- 18 cm cuff.
- For more information and regional pricing, visit castelli-cycling.com.
- You can read more about the Castelli ‘Hot Weather’ kit in the PEZ Gear Break.
- The short videos were made using an AKASO 360, a full preview coming soon on PEZ. More info HERE and the AKASO 360 can be bought from AMAZON.COM.
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