Measurements are presented of the terrace width distribution on a vicinal copper surface with (1 1 13) orientation as a function of temperature. Assuming a mean field model, we determine the strength of the step-step interaction from the width of a Gaussian fit. Based on the value for the strength of interaction, the expected terrace width distributions for Cu (1 1 7) and Cu (1 1 11) at room temperature are calculated and compared to earlier measurements on these surfaces. in addition, an analysis of a data set of STM images of the Cu (1 1 19) surface at temperatures above room temperature is discussed. All of the experimental data are well described by the measured value for the step-step interaction strength on the Cu (1 1 13) surface. From the interaction strength we obtain a rough estimate of the roughening temperatures of Cu (11n) surfaces.