In order to understand the buffering behavior of hygroscopic fabric under subzero conditions, microclimates of the wool and PET clothing system were measured and compared. Vertical type Man-Clothing-Environment simulator was used to measure the microclimate at the environmental temperature of -10℃ Buffering capacity was quantified by calculating from the depth and width of the hyperbolic curve of the graph. Hydrophilic wool fabrics showed better buffering capacity at the transient state than hydrophobic PET fabrics; which is attributed to the heat of sorption.