  We use results of shallow-water magnetohydrodynamics (SWMHD) to place
estimates on the minimum magnetic field strengths required to cause atmospheric
wind variations (and therefore westward venturing hotspots) for a dataset of
hot Jupiters (HJs), including HAT-P-7b, CoRoT-2b, Kepler-76, WASP-12b, and
WASP-33b, on which westward hotspots have been observationally inferred. For
HAT-P-7b and CoRoT-2b our estimates agree with past results; for Kepler-76b we
find that the critical dipolar magnetic field strength, over which the observed
wind variations can be explained by magnetism, lies between $4\mbox{ G}$ and
$19\mbox{ G}$; for WASP-12b and WASP-33b westward hotspots can be explained by
$1\mbox{ G}$ and $2\mbox{ G}$ dipolar fields respectively. Additionally, to
guide future observational missions, we identify $61$ further HJs that are
likely to exhibit magnetically-driven atmospheric wind variations and predict
these variations are highly-likely in $\sim 40$ of the hottest HJs.
