Every clothing review should also provide the rider's info as well as size. So many are missing this info and it's so hard to find the right fit many times: I'm 5'8" / 155lb / male and ordered a Med and It's a bit tighter than some, but still fits. I think a Large would be too big.
This is better for a cool / cold days with or without lots of layers. I can use this with short sleeve base (or long sleeve if colder) and it works fine. I used it recently on a century ride where we started out in low 50's and rain off and on throughout the day. I had a gilet over top for some extra warmth until it warmed up into the 60's but I was still comfortable in this. Even though we got wet on the outside, I didn't get soaked completely through. So it's not waterproof but it good enough to trust in wet conditions to stay warm depending on your length / comfort level.
It's a good piece to have in the arsenal depending on conditions. If there's a biting wind, I trust this to block a lot more wind than many of the other long sleeve jerseys I have. So this is probably a good deep fall / early spring jersey depending on your particular climate. I would use this down to 40's (or maybe lower) but would just layer up a bit more depending on the actual temp and time of day I was riding. I think it's great.
Very well made and good quality. I will take issue with the idea that this jersey helps with wind and can be worn in colder temperatures. I do not wear it by itself if it is under sixty. Under sixty I will wear it underneath a jacket and I still feel cool wind on my arms. Used as a layer under a jacket seems to work well but it definitely is not as good as it is described. I usually wear a small and this small fits me a little more snug than most. I will give it a pretty good but not great rating.
Bought the blue in XL and the Red, which is really safety cone orange in XL. Both measure different. Obtained measurements from castelli Customer service. Blue measures a L but fits me better.