The Year Without a Summer (also known as the Poverty Year, Year There Was No Summer, and Eighteen Hundred and Froze to Death) was 1816, in which severe summer climate abnormalities caused average global temperatures to decrease by about 0.4–0.7 °C (0.7–1.3 °F), resulting in major food shortages across the Northern Hemisphere. It is believed that the anomaly was caused by a combination of a historic low in solar activity with a volcanic winter event, the latter caused by a succession of major volcanic eruptions capped by the 1815 eruption of Mount Tambora, in the Dutch East Indies (Indonesia), the largest known eruption in over 1,300 years.

Historian John D. Post has called this "the last great subsistence crisis in the Western world"