Year Without a Summer

The year 1816 is known as the Year Without a Summer because of severe climate abnormalities that caused average global temperatures to decrease by 0.4–0.7 °C (0.7–1 °F). Summer temperatures in Europe that year were the coldest of any on record between 1766 and 2000, resulting in crop failures and major food shortages across the Northern Hemisphere.

Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive eruption of Mount Tambora in the Dutch East Indies (modern-day Indonesia) in April 1815. This eruption was the largest in at least 1,300 years (after the hypothesized eruption causing the volcanic winter of 536); its effect on the climate may have been exacerbated by the 1814 eruption of Mayon in the Philippines. The volcanic ash and gases released into the atmosphere blocked sunlight, leading to global cooling.

The United Kingdom of Great Britain and Ireland and Bourbon Restoration France experienced hardship, with food riots and famine becoming common. The situation was exacerbated by the fact that Europe was still recovering from the Napoleonic Wars, adding to the socio-economic stress.

North America also faced extreme weather conditions. In the eastern United States, a persistent "dry fog" dimmed the sunlight, causing unusual cold and frost throughout the summer months. Crops failed in regions such as New England, leading to food shortages and economic distress. These conditions forced many families to leave their homes in search of better farming opportunities, contributing to westward expansion.