H-manwrote a review of Castelli Idro Jacket - Men's on November 9, 2017
Familiarity: I've used it several times
The Idro jacket definitely fit the bill for me in many ways. I didn’t get to wear it in a steady rain, so the jury is still out on it being waterproof. It is amazingly lightweight, warm in chilly conditions and *extremely* packable to a size to readily fit in a jersey back pocket.
When cruising along at 18+ mph, you will get wet from sweat while wearing the Idro. I guess there just isn’t a perfect trifecta cycling jacket of waterproof, packable and completely breathable. At least not at pace or over 30 minutes riding.
The jacket’s sizing is definitely small. I am 5’, 11” and 195. I usually wear a size large or XL. I ordered the XXL and was very pleased with its fit.