Summer is warm, so people will wear lighter clothes, short sleeves, skirts, shorts, and lightweight-fabric pants, indoors and outs. In the evenings it gets cooler and people might put on a sweater.
In Fall and Spring it is cool but not cold. If it isn't raining people are likely to wear long sleeves, long pants or jeans indoors, adding to that a light jacket or a sweater outdoors. If it is raining the jacket is likely to be water-proof.
Winter is rainy, and cold but usually not freezing. sometimes there is snow for maybe a week or so, but usually not for much longer than that.
In Winter people will wear heavier coats or jackets outdoors, and warm pants and shirts and sweaters or sweat-shirts. People will often wear rain-boots, and snow boots when it snows, if they are prepared to do so. Some people will wear gloves and hats in the winder but many don't, as it isn't usually very cold, just moderately cold and rainy. Of course in a building people will take off their boots and coats, and so all of this is for outside. Inside in winter, people wear ordinary warm clothes -- long-sleeves, long pants, maybe a sweater or sweatshirt.