A backward-elimination, multiple-regression analysis was used to determine which meteorological factors significantly explained the variation measured in concentrations of allergenic spore forms 1.5 m above ground level. Airspora were collected for three years (1976–1978) with volumetric samplers. Adequate moisture is probably the most important variable in spore production. In the imperfect fungi, once the spores are produced, release is often influenced by wind velocity. In the Ascomycetes, radiation, minimum humidity, changes in humidity, and minimum wind velocity were all directly correlated with airborne ascospores, while in the Basidiomycetes, precipitation was the most important variable directly correlated with basidiospores in the atmosphere.