We’ve seen a roller-coaster of summer weather, with high temperatures and record lows. But in 1816, much of the northern hemisphere saw what was called the “Year without a Summer”. New England saw freezing temperatures in June, July and August. In Canada, many small lakes were still frozen in July. Europe fared no better. In Ireland, cold rain fell on 142 of 153 during the summer of 1816. Food riots broke out in Switzerland and France. The cause: a volcanic eruption. Mount Tambora erupted in April of 1815, on an island east of Bali. By the time the eruption ended on April 12th, a foot-thick layer of ash covered the sea. And profound darkness persisted for as much as 3 days up to 200 miles from the explosion. The enormous clouds of ash were propelled into the atmosphere, bringing the global cooling noted half way around the world.
Mary Knapp, Weather Data Library