Summary of five models from different phases of solar cycle 24. The first column shows 3D renderings of the PFSS models, with open magnetic field lines coloured by surface rotation rate (see Fig. 1). Closed magnetic field lines are shown in grey. The solar surface is coloured with red and blue representing the radial magnetic field used in each PFSS model, and the location of the Heliospheric Current Sheet (HCS) is indicated in black at the source surface. The middle column displays the same information projected on a latitude-longitude grid. The final column shows the effective rotation rate of field lines at the source surface (R_ss = 2.5 R_⊙). These values are acquired by tracing field lines down to the surface, and returning the value of the surface rotation rate (this is the same as for the colour on the field line renderings). The mean value of the effective rotation rate ⟨Ω_wind⟩ is listed with each model (the Carrington rate is ∼456 nHz).