The elasticity of a rubber band is inversely related to temperature, meaning that as temperature decreases, elasticity increases. This is because the polymer chains in the rubber band become stiffer and less able to move when it is cold, making the rubber band less elastic. Additionally, the glass transition temperature of the rubber band, which is the temperature at which the polymer chains become immobile and the rubber band becomes hard and brittle, decreases with increasing temperature. This means that the rubber band will become brittle at a lower temperature when it is cold, making it even less elastic.