Mount Tambora is on the island of Sumbawa in present-day Indonesia , then part of the Dutch East Indies . Although its eruption reached a violent climax on 10 April 1815 , increased steaming and small phreatic eruptions occurred during the next six months to three years . The ash from the eruption column dispersed around the world and lowered global temperatures in an event sometimes known as the Year Without a Summer in 1816 . This brief period of significant climate change triggered extreme weather and harvest failures in many areas around the world . Several climate forcings coincided and interacted in a systematic manner that has not been observed after any other large volcanic eruption since the early Stone Age . Although scientists have proven that the post-eruption climate changes and the Tambora eruption are linked , they have only an incomplete understanding of the processes involved
Year Without a Summer
Year Without a Summer
1815 eruption of Mount Tambora