Outdoor air-sampling surveys were conducted in February, May, August and December 1992 with a Samplair-MK1 particle sampler at 50 randomly chosen sites in the Kitchener-Waterloo area of southern Ontario, Canada. Canonical Correspondence Analysis of the resulting data revealed that the influence of some environmental factors on the airborne fungal spora varied with the season of the year. Among the 16 environmental factors measured at each sampling time, the most important were found to be: relative humidity, rain, vegetation, cloud, temperature, and wind speed, in descending order. The composition of the airborne fungal spora also changed with the season. The dominantCladosporium, AlternariaandAspergillus + Penicilliumwere found at all seasons, butGanoderma, Leptosphaeria, Coprinus, and Polythrinciumoccurred mainly in summer. Positive relations were revealed between, on the one hand, (1a) relative humidity, (1b) rain, (1c) cloud and (1d) temperature, and on the other hand, (2) high spore counts ofLeptosphaeria, Xylariaceae, unidentified Ascomycetes, andGanoderma. A similar relationship was detected between (1) vegetation and (2)AlternariaandOidium. (1) Higher wind speeds were positively related with (2) hyphal fragments and relatively large spores, such as those ofDrechslera, Nigrospora, Periconia, andOidium. Canonical Correspondence Analysis provides both a new approach to the analysis of aeromycological data and informative graphical presentations of the results.