What and when was the year with no summer?

According to Acts of God: The Old Farmer’s Almanac Unpredictable Guide to Weather & Natural Disasters, the year without a summer was 1816. In 1815, the volcano Tambora erupted in Indonesia. The volcano’s heavy ash, column of dust, and sulfurous gases rose into the stratosphere, and swift winds spread them around the globe. The hazy shroud caused the sun to appear dull and reddish over the next few years. In 1816, it snowed in New England in July. Snow and killing frosts occurred throughout the northeastern United States and Canada in June, July, and August. The corn crop was abysmal, and the poor farming conditions caused many New Englanders to relocate. The cold reached across the Atlantic to Europe, making it impossible to grow crops there, which spawned widespread famine.