The year 1816 is called the "year without a summer" because of this.
Ten months of snow
Locust invasion
Calendar error
Icebergs in Atlantic
Volcanic eruption
Volcanic eruption. In mid-April, Mt. Tambora in Indonesia exploded with a force that reduced it from 13,000 feet to less than 9,000. So much volcanic ash circulated in the world’s atmosphere that temperatures were lowered dramatically, causing many crop failures in North America and Northern Europe.