The disclosure describes a user interface that may be used to control ablation therapy and monitor ablation therapy progress in systems that utilize wet electrode ablation techniques. The user interface presents a virtual electrode depth icon to a user that indicates the size of a lesion that may be created with the selected virtual electrode depth. The virtual electrode depth may be changed by the user according to the ablation therapy most appropriate for a patient, and the user may interact with the user interface to define the virtual electrode depth. In this manner, the user interface may be a touchscreen or other input device such as a mouse, pointing device, or keyboard. The user interface may also provide a thermometer icon that represents a patient temperature, a timer icon that represents a remaining time for therapy, and other representations of therapy progress.