While a wide range of software applications allow users to manipulate time-based data, or time series, they all work with user interfaces designed with specific affordances related to time. This article investigates how interfaces help users capture, manipulate, and understand time series data. By exploring how user interface elements of time-based software applications address seven User Time Needs, the authors propose a set of nine different interface design patterns called timeline navigators that generalize across applications. While existing research evaluates specific time-based interface elements, the authors have not seen a framework for considering time-based interface elements and users’ corresponding underlying needs more generally across software domains. The analysis provided is intended to help designers become aware of the major practices and conventions found in timeline navigators as well as the user needs that they support.