This article explores documentary evidence of droughts in Sweden in the pre-instrumental period (1400-1800 CE). A database has been developed using contemporary sources, such as private and official correspondence letters, diaries, almanac notes, manorial accounts, and weather data compilations. The primary purpose is to utilize hitherto unused documentary data as an input for an index that can be useful for comparisons on a larger European scale.

The survey shows that eight subperiods can be considered as having been particularly struck by summer droughts, causing concomitant harvest failures and having great social impacts in Sweden. This is the case with 1634-1639, 1652-1657, 1665-1670, 1677-1684, 1746-1750, 1757-1767, 1771-1776, and 1780-1783 CE. Within these subperiods, 1652 and 1657 stand out as particularly troublesome years. A number of data for dry summers are also found for the middle decades of the 15th century, the first decade of the 1500s, and the 1550s.