Why 1816was called the year without a summer?

The year 1816 is known as the "Year Without a Summer" due to severe climate abnormalities that led to unseasonably cold temperatures across the Northern Hemisphere. This phenomenon was primarily caused by the eruption of Mount Tambora in Indonesia in 1815, which released large amounts of volcanic ash and sulfur dioxide into the atmosphere, blocking sunlight. As a result, many regions experienced frost and snow during the summer months, leading to failed crops and food shortages. The unusual weather patterns had significant social and economic impacts, particularly in parts of North America and Europe.