Twelve Years of Daily Weather Descriptions in North America in the Eighteenth Century (Mexico City, 1775-86)

The weather diary of Felipe de Zuniga y Ontiveros was recorded in Mexico City from 1775 to 1786. It is the earliest meteorological observational record of Mexico. The diary provides daily meteorological information for rain frequency, temperature, frost, hail, thunderstorms, and wind, with higher resolution than any other contemporary documentation or natural proxy from this region. The seasonal distributions of rainy days, temperature, hail, and thunderstorms correspond well with those from the Tacubaya Observatory in Mexico City (1886-2016). Two drought periods (1780/81 and 1785/86) and one wet period (1782/83) were identified. The drought spanning from 1785 to 1786 is known in the literature as the hunger year because it represented the most severe famine during the colonial period (1521-1821). This paper analyzes-for the first time-this event at a daily scale. Similar to the reported droughts of 1909/10 and 2010/11, 1785/86 was a very dry period. But the dry conditions of 1785 were followed by intense frosts that started in late August and continued through September and October. This combination led to the destruction of crops and subsequent famine. The duration of the frost does not have analogs during the instrumental period, probably because of the intense warming and land changes registered over the last years in the region.