Magnetospheric dynamics at Earth are driven by coupling between the magnetised solar wind and the magnetospheric magnetic field and plasma. Numerous studies reveal that the magnetosphere exhibits a non-linear response to solar wind drivers, with saturation observed under strong external forcing. Whilst this saturation could be the consequence of a physical process, another possibility is that the uncertainties in the time delays applied by OMNI, to propagate measurements from the L1 Lagrange point to the bow shock nose, introduce a “regression to the mean” effect. Instead, Cluster’s orbit allows in-situ monitoring of upstream solar wind conditions for part of each orbit during several months of each year. When located in the solar wind, delays between Cluster and the bow shock are of the order of few minutes rather than an hour for OMNI data. By using ESA’s Geospace Region and Magnetospheric Boundary identification (GRMB) database, we can f ilter Cluster data to isolate pristine solar wind data and compare these measurements with OMNI predictions to investigate inaccuracies in OMNI’s time propagation. Early findings will be presented that outline the comparison between the datasets, discussing potential implications for investigating solar wind–magnetosphere coupling.