Infrared (IR) thermography was used to monitor the drying of water from both smooth and rough surfaces. An analysis using the coefficient of variance (COV) of the temperature shows the point at which surface dryout begins. The dry spots that develop on a surface lead to temperature variations across the surface. The COV reflects these variations and is a sensitive measure of the early stages of dryout. The shape of the COV profile as the surface approaches dryness depends on the roughness of the surface. For rough surfaces such as wood, the COV climbs because differences in heat transfer to the heterogeneous wood surface are accentuated. Changes in the COV are much smaller for polymer films deposited on metal surfaces but are still dependent upon surface roughness.