A weather resistive barrier (WRB) for the exterior protection of building substrates can have a water vapor permeability that decreases with increasing temperature. In an embodiment, the WRB includes a coating comprising a LCST polymer, and may further include a second polymer. The WRB can be part of a building assembly, part of a sheet, or a sheet itself, the sheet having an air permeability of less than 0.02 L/(s m2) at a pressure of 75 Pa. Furthermore a liquid coating composition can include a LCST polymer and a second polymer, wherein the liquid coating composition can be adapted that a solid coating formed by the liquid coating composition has an air permeability of less than 0.02 L/(s m2) at a pressure of 75 Pa and a water vapor permeability that decreases with increasing temperature.