The Dalton Minimum was a period of low solar activity, named after the English meteorologist John Dalton, lasting from about 1790 to 1830.[1] Like the Maunder Minimum and Spörer Minimum, the Dalton Minimum coincided with a period of lower-than-average global temperatures. The Oberlach Station in Germany, for example, experienced a 2.0°C decline over 20 years.[2]
The precise cause of the lower-than-average temperatures during this period is not well understood. Recent papers have suggested that a rise in volcanism was largely responsible for the cooling trend.[3]
While The Year Without a Summer, in 1816, occurred during the Dalton Minimum the prime reason for that particular cold spike was the eruption of a Super Colossal Volcano named Mount Tambora in Indonesia which was (jointly) one of the 2 largest eruptions in the past 2000 years.
A detailed analysis with the auroral and solar data has been given by Wilfried Schröder, N. N. Shefov in a paper in Ann. Geophys. 2004. Also details can be found in Wilfried Schröder, Das Phänomen des Polarlichts (The Aurora in Time), Darmstadt, Wissenschaftliche Buchgeselllschaft 1984, and Science Edition, Bremen, 2000.