Using a substorm onset list from the Imager for Magnetopause to Aurora Global Exploration (IMAGE) and Polar satellite images, we have constructed a new dataset of 63 substorm onsets observed in both hemispheres and their locations. We find that incorporating the history of the interplanetary magnetic field (IMF) improves the predictive power of IMF By in explaining conjugate displacement in Magnetic Local Time (MLT). Our dataset, approximately five times larger than in previous studies, enhances statistical power and focuses on the substorm onset feature. This allows for better correlation of IMF By with MLT conjugate displacement (ΔMLT), since it has been shown that IMF-induced By tends to diminish as substorms progress. In line with previous work, we find a linear relationship between IMF By and ΔMLT, though with a shallower gradient. Additionally, we analyse predictors of conjugate displacement in Magnetic Latitude (ΔMLat), showing that dipole tilt (ψ) is the strongest predictor. However, we find that this relationship is not strictly linear, and that a larger dataset and a better understanding of the physical mechanisms are needed to more accurately capture the exact functional relationship between ψ and ΔMLat.