The jacket holds pretty well in the rains. The inner liner is waterproof so that's a big bonus

. It does not have a hood though so if u intend to walk in heavy rain with the Rjays on, then you might just get wet with the water seeping inside from top!
ABout winters, well no clue honestly! Winter hasn't come yet in mumbai! :P
Though the thing is that the jacket is a mesh one so I am sure if won't be suitable for the winters. But one can always attach the rain liner inside to keep oneself relatively warm inside.
I had asked bacho motors for a quilt liner (Winter liner) for the swift but sadly a quilt liner isn't made for the swift jacket.
Bottomline: if you are riding in the rain the rjays will keep you dry but in winter it may not be able to keep you warm (this is an assumption yet)