I use it everyday as a commuter glove. It keeps my hands fairly warm down to about 40 degrees. It does fine in a drizzle but will soak through a bit in a steady rain.
Okay, I use to never ride in the rain or cold even semi cold but then I got a pair of Castelli NanoFlex tights and they worked so well I followed that purchase up with the NanoFlex arm warmer and now this Perfetto Light jersey. I should have purchased two of them becasue I use it just about everytime I ride. If it's colder out I use a merino base layer if it's warmer I use a light base layer or nothing at all. The fabric on this keeps the wind and rain off you yet breaths so well it feels like you are riding on a nice summer day with just a light jersey on even in the rain. Fanatic!!!!
Simple awesome, best cold weather tight I've ever used. The red fleece fabric feels dry even when it's wet, super warm down to 15 degrees. Don't know how they do it but Castelli makes the best stuff period.