12 inches of snow fell in Quebec City in June, and rivers were frozen as far south as Pennsylvania well into August. The combination of the massive volume of volcanic ash pumped into the atmosphere causing sunlight to be partially blocked, along with a decrease in general solar activity led to this bizarre weather pattern.
Mount Tambora today.
A somewhat similar incident happened in 1883. during the eruption of Krakatoa. Weather was not affected to the extent as what happened with the Mount Tambora eruption (weather only went down 1.3 degrees Fahrenheit worldwide), but the explosion was catastrophic. A clogged lava pipe led to the mountain exploding, which was heard literally around the world. Ships all the way to South Africa were affected a resulting tsunami that killed over 30,000 people in Indonesia. To this day, it is the largest explosion ever recorded. The amount of ash propelled into the sky caused changes in light during sunsets. People saw more vivid colors, and brighter colors in the sky at sundown for months after the eruption. It was theorized that the background of Edvin Munch's famous painting, "The Scream" was inspired by the sunsets after the explosion.
Mount Kraktoa was destroyed in the explosion in 1883, and laid under the Pacific floor until the 1930's when it came back after some underwater eruptions caused it to reform.
I had heard of the Kraktoa explosion because of a PBS documentary I had seen about a year ago, but I hadn't heard of Mount Tambora until recently. A fiction book called Supervolcano Eruption by science fiction/alternate history writer Harry Turtledove, which looked at the possibility of an explosion in Yellowstone National Park that would be similar to a combination of Mount Tambora and the Krakatoa eruptions, introduced me to the history of Mount Tambora.