Forecasting the start and severity of the hay fever season


Dr R. R. Davies, St Mary's Hospital Medical School, London, W2 1PG.


Since the season of summer hay fever may last only 4 weeks and rainfall may produce days with virtually no airborne pollen, the timing of clinical trials is important. To facilitate this a method of forecasting the first possible 100% symptom day, and the severity of the season in terms of light, moderate or severe, is presented. The forecast is based on temperature in April and May, and formulae tested by reference to records of grass pollen concentrations over Central London during 1961–70.