Because of its woven and the way the trims are, tweed is warmer than other wool fabrics. However, there are many kinds of tweed. The weight is important to know how warm they are. We know tweed fabrics are getting really popular because of the vintage wedding trend and Peaky Blinders, so it is something to be considered for summer day weddings. Choose unlined jacket option if you want a lighter and fresher tweed suit. This is why some people consider tweed as a 3 season suit so they try to avoid it during summer.
So, what season should I wear a tweed suit? As far as it is comfortable for you, you can wear it all year long, below your overcoat or as an outwear jacket. Then during summer, you will have to consider the external temperature and check the weight of the fabric and unlined jacket options.
Is a tweed suit warm for winter? Depending on where you live, in some places, it can be a good outwear winter jacket, in others, you will actually need a good overcoat.
Is a tweed suit itchy? The tweed fabric from your suit jacket shouldn't be in contact with your skin. In addition, some tweed fabrics are softer than a standard wool mill.
Is tweed breathable? While it is true that it is warm, it is yet breathable. All wool fabrics are breathable as they keep the same natural purpose as with the sheep: keep it warm but letting the airflow. The level of breathability will depend on the kind of tweed fabric and its thickness.