This paper discusses select impacts of ambient temperature variations along a transmission line on voltage attenuation and power handling capabilities. Temperature-dependent models are developed and used in simulation to study these impacts. In order to capture the non-uniformity of line parameters caused by ambient temperature gradients, these models are characterized by multiple lumped segments which are non-uniform in length and parameter values. A case study for a medium-length line and several ambient temperature scenarios is presented and underlines the sensitivity of the line performance on temperature gradients.