Abstract. Asynchronous remote usability testing is a method based on a software platform used to automatically record test participants' activities when they interact with a given product in their natural environment, for example, at home. This method has been frequently used in previous decades in web design and mobile application development but has rarely been utilised in geovisualization. The importance of remote usability testing has rapidly increased in 2021 due to the COVID-19 pandemic. The 3DmoveR (3D Movement and Interaction Recorder) application was used for asynchronous remote testing presented in this paper. 3DmoveR is a research tool designed for user testing of interactive 3D visualizations in web browsers using open technologies such as PHP, JavaScript, and the Three.js library. This study focuses on an evaluation of interactive 3D city models presenting thematic information expressed by colour scale. An experiment was designed as a within-subject study consisting of two simple questionnaires, a training task and six experimental trials. Finding a building of a given category (depicted as building colour) within an interactive 3D city model was used as the experimental task. Speed and accuracy of user performances were recorded, as well as user strategy, subjective evaluations, and possible intervening variables. The results were recorded from 110 participants, where 76 of them were correct and analysed further. It can be concluded that the tested colour scale (based on the Energy Performance Certificate) was not entirely appropriate. We further analysed and discussed intervening variables that may affect remote usability testing of 3D visualizations.