The 'Year Without a Summer' was a climatic anomaly that affected the United Kingdom in 1816. It was largely caused by the eruption of Mount Tambora in April 1815, which released vast amounts of volcanic ash into the atmosphere, reducing sunlight and leading to cooler temperatures. This drastic climate change resulted in agricultural disruption, crop failures, and food shortages. The consequences included economic distress, widespread hunger, and social unrest as communities struggled to adapt, prompting significant societal challenges.