The Saint Santin (45 N) incoherent scatter radar data base shows a local enhancement in nighttime ion temperature that occurs in winter only. Its amplitude can exceed 100 K and averages 40 K on the basis of a conservative computation. The enhancement peaks near 4 LT and has a duration of about 4 hours. We discuss two possible explanations for this feature: (1) it is caused by the convergence of global winds at the global pressure minimum, under which Saint Santin rotates at winter solstice, and (2) it is an extension or propagation of the well-known low-latitude midnight temperature maximum to midlatitudes, perhaps to that pressure minimum.