Daily weather mapping from 1781:

An account is given of the preparation of daily weather maps within the historical-instrumental period, with details concerning the detection and location of source material and its subsequent examination, collection and reduction to provide a workable synoptic network of comparable meteorological observations over the eastern North Atlantic-European sector. The application of the Lamb British Isles weather types and Grosswetterlagen for the statistical analysis of circulation patterns derived from these charts is discussed. An objective test was devised whereby the frequency of monthly extremes of nine variables was examined with the following important conclusions:

1. the synoptic charts of the 1780s show no evidence of systematic errors when compared with rainfall figures,
2. the early 1780s was a period of unusually high climatic variability on the month-to-month time-scale, especially in the frequencies of cyclonic and of anticyclonic days.

An account is given of the impact of climate on the affairs of man in the 1780s, highlighting some specific historical case studies and discussing agriculture and industry in general.