A jacket should be one of the key items in your cycling wardrobe, more the merrier in fact - one for all seasons! No matter how many layers you have on, a jacket, or lack of one could make or break your ride. Ultimately it is the individual's preference for what kind of jacket and which material is most suitable, but always aim for a breathable fabric that provides ventilation and prevents you from steaming up.
A jacket that fits snug will be more beneficial than a jacket flapping in the wind due to the wicking characteristics. The closer to the body the more efficiently the fabric can do its designed purpose - to absorb and wick away moisture whilst trapping warmth when necessary. Not only can a jacket be the perfect barrier against rain, wind and cold it can also provide UV protection and absorb sweat, helping you remain dry - riding more comfortably, for longer, all year round.