(a) Peak velocities of three recurrent HSSs, which were observed a total of 15 times by the Helios satellites at 1 au in 1973, vs. the areas of their source coronal holes (data from Nolte et al. 1976). (b) Peak velocities of 115 HSS observations by the Advanced Composition Explorer (ACE), Stereo A, and Stereo B during 2010–2017 vs. the areas of their source coronal holes. The absolute value of the latitudinal separation angle between the satellites taking the HSS measurements and the center of mass of their source coronal holes are color-coded (data from Hofmeister et al. 2018). (c) Peak velocities of 47 HSS observations by ACE in 2016 and 2017 vs. the longitudinal extensions of their source coronal holes; outliers are marked in red (data from Garton et al. 2018).