Eczema-prone skin often holds steady through the summer months only to become noticeably more reactive as temperatures drop. The shift isn't about one single factor. It's the combination of drier outdoor air, the onset of indoor heating, a change in what you wear, and subtle shifts in your daily rhythm that together place greater demand on a skin barrier that was already working harder than average. Understanding how these forces interact makes it easier to adjust your routine before irritation builds into a full flare, rather than responding after the skin is already inflamed.