Transitional season adaptability when the weather is chilly but not freezing a thermal jersey is a great option the fleece fabric of this excel jersey traps a layer of warm air inside providing insulation against the cold outside the fabric is also breathable allowing moisture to escape as you build up heat so you don39t feel damp and chilly worn with a light base layer on milder days it will give you extra comfort compared to a standard jersey and arm warmers or as temperatures fall use