yea, climate affects our engines greatly, especially if they are carbbed. Just riding during the day and then during the night makes a difference, on cool weather the bikes generally perform better because they dissipate heat more easily and cold weather is rich in oxygen that benefits performance on our bikes so u will find a more responsive bike during cool weather.... cold weather is quite differente because if it is too cold, it robs too much engine heat and that at the same time robs heat from the combustion chamber affecting combustion itself, since gasoline needs also need heat to ignite
as far as vibrations are affected... I really haven't tried it out to see if the vibrations lessen... although... if ur riding in cool weather without a jacket u might feel ur own body vibrations rather than the engine's

 

Pull a plug wire off to get that Harley feel.,,