The paper describes the asymmetry in the seasonal variations of the critical frequency of the F2 layer at high‐latitude stations in the northern and southern hemispheres during the years of minimum sunspot number. The variations of the F2 layer at pairs of stations similarly situated on opposite sides of the equator are studied for different hours of the day and for different stages of solar activity. During years of low sunspot number, the curves of seasonal variations of foE, foF1 as well as foF2 are very similar to each other, and the well known summer decrease of noon foF2 is not present at southern stations. The various hypotheses advanced to explain the abnormalities in the F2 region are examined to explain the asymmetry, and a plausible cause is suggested on the basis of wind systems in the F2 region, mainly the horizontal transport of the ionization.