By means of regression analysis theCladosporiumandAlternariaspore counts for 1980–89 for Stockholm are explored and modelled at 6-hour intervals in order to find the relationship between spore presence and climate for the same time periods. Six different weather parameters are used. ForCladosporiumdaily mean temperature and daily precipitation seem to be consistently significant. The presence ofAlternariaappears to be more complex. There is a tendency forAlternariaspore concentrations to increase with the daily precipitation, wind velocity and total cloud cover. The models are evaluated statistically.