The year 1740 was the coldest in Central Europe since at least 1421. New monthly, global climate reconstructions together with daily weather reconstructions allow a detailed view of this climatic event. Following several severe cold spells in January and February, a persistent circulation pattern with blocking over the British Isles caused northerly flow towards Western Europe during a large part of the year. It was one of the strongest, arguably unforced excursions in European temperature.

We have digitized and analyzed meteorological variables (temperature, direction of the movement of the clouds, and cloud cover), which were noted by Louis Morin in the period 1665–1713 in Paris. This time period is characterized by cold winters and autumns and moderate springs and summers. A low frequency of westerlies in the winter months leads to a cooling. Morin's measurements seem to be trustworthy. Only cloud cover in quantitative terms should be taken with caution.

Droughts derive from a precipitation deficit and belong to the most dangerous natural hazards for human societies. Documentary data of the pre-modern and early modern times contain direct and indirect information on precipitation that allows for the production of reconstructions using historical climatology methods. For this study, two drought indices were created on the basis of documentary data produced in Bern, Switzerland, and Rouen, France, for the period from 1315 to 1715.

Early colonial documentary records offer valuable climatic and historical information, but their reliability and suitability for climate reconstruction and environmental history remain uncertain. This study systematically compares drought information from records of colonial expeditions in North America 1510–1610 CE with high-resolution PDSI reconstructions of the North American Drought Atlas. It finds substantial agreement, and it suggests potential uses for such records and reconstructions.