Seventy-nine patients suffering from rheumatoid factor positive rheumatoid arthritis (RA) were included in this study. In each patient disease activity was assessed three times at two-week intervals during a four-week period. All factors that might possibly influence RA, except atmospheric conditions (AC) were held constant as far as possible. Current AC parameters were obtained from the local observatory of the Royal Dutch Meteorological Institute. There were no relevant correlations between AC and RA variables. Also relations between changes in AC variables preceding the disease activity assessment or between changes in AC variables and RA variables were not seen. By means of factor analysis, uncorrelated factors pertaining to RA or to weather were extracted. No clear association between any of the AC variables and any of the RA variables was noted. Our results do not support the widely accepted, but insufficiently documented, influence of weather on RA.