Using recently derived-values of the water vapor dimer spectral absorption cross section wecalculate the water vapor dimer contribution to the clear sky absorption of solar radiation. Weconsider the water dimer concentrations deduced from local equilibrium thermodynamics, andwe account for the overlap of water vapor dimer and monomer absorption bands. We estimatethat water vapor dimer contribution to the clear sky broad band column absorption of solarradiation is around 3 and 6 W/m2 for the cases of midlatitude summer and tropical atmosphere,respectively, at the solar zenith angle of 30°. For the cases of midlatitude winter, the US standardatmosphere and subarctic winter atmosphere, the dimer contribution to the absorption of solarradiation is less than 1 W/m2. Due to an uncertainty of the dimer’s concentration within clouds,we are not able to deduce, at this time, the dimer absorption in a cloudy atmosphere. DOI: 10.1034/j.1600-0870.1999.t01-2-00010.x