The relevance of allergy skin prick testing in the diagnosis and treatment of seasonal allergic rhinitis and pollen asthma can usefully be interpreted in relation to the timing and duration of seasonal symptoms and the presence of pollen and mould spores in the air. This calendar has been constructed from three years continuous observations of pollen andAlternariamould spore counts between January 1993 and December 1995, using a Burkard 7‐day volumetric spore trap. Of the total airborne pollen, tree pollen comprises 65%, weeds and herbs 11% and grasses 18%. Unidentified pollen, “other”; group, accounts for6%of the total airborne pollen. The most numerous of the tree pollen is that of the introduced trees cypress(Cupressusspp.) and privet(Ligustrumspp.). Grass pollen is seen in small numbers throughout the winter but shows a rapid increase in spring to peak in mid to late November. Weeds pollinate from early spring through to summer.Alternariamould, which is a risk factor for childhood asthma, occurs mainly in late spring and summer but is present in small numbers intermittently throughout winter.