The relationship between monthly Ischaemic Heart Disease mortality and mean monthly temperature and rainfall is examined using data for England and Wales covering the period 1968 to 1976. The statistical procedure adopted involves a time series analysis of each of the individual series employing an approach which has become increasingly popular in other sciences over the last decade. Results indicate the correlation coefficients quoted in previous studies involving monthly data are spuriously high implying that temperature is not as closely related to Ischaemic Heart Disease deaths as has often been claimed.