The mole fraction x2 of the ozone dimer in its equilibrium mixture with the monomer is evaluated on a base of recent ab initio correlated quantum-chemical computations. The dimerization equilibrium constant is evaluated in terms of partition functions. The pressure and temperature profiles are taken from observations in Antarctic conditions. The resulting x2 altitude profiles exhibit dependencies with maxima and minima. The seasonal dependency follows that known for the ozone partial pressure. Depending on the computational treatment applied, the highest x2 values found are of the order of 10(-8)% or 10(-10)%.