Mid-season jacket can be worn all year round. That is, if the summer is cool and winter warm. Although this happens very rarely. Why "demi"? - and the French have tried! Demisaison -the transitional time of the year, i.e. autumn and spring.
Yes, mid-season jacket can be worn, but only if you have it. And if not? We proceed from the fact that if not, will buy and will still wear it! And here it's just to stop and think, what kind of jacket to choose from the great variety? What length? Should it be hooded? And if so, whether or not the hood to release? The climate in which you live? Depends on whether you want the jacket to be sewn from waterproof material, at the same time, do not let a strong wind. In other words, should the jacket to serve as a windbreaker? It is desirable to have pockets? Should it be equipped with a detachable lining? What is your budget for this purchase? A lot of things, including weight, style and color.