I think the Blizzard of 1888 and similar bad weather elsewhere was the last gasp. In 1815, Tambora (5 mile diameter crater)was an even larger eruption giving us the Year With No Summer in New England and elsewhere, 1816. Also there were major floods in North America in 1821/22. After Pinatubo (3 mile crater)in 1991 the weather was crazy for up to 5 or 6 year. I remember there was one ice storm in New England/Canada that coated trees and power lines with 1” of ice with major destruction and collapse. I forget the year. There might not be a major crater in Iceland for that period. A major eruption there in 1783 was at the Laki Fissure. Ben Franklin remarked on the weird weather in Europe where he was in diplomatic service. It also caused crop failures which helped trigger the French Revolution.
Cassiodorus (Roman) also wrote about the strange weather. Swiss Alps were in a good position to record Icelandic eruptions. I suspect more so than Greenland which also has ice cores.
Ice core data from Greenland has been used to date eruptions, but not all of those eruptions have been attributed to any known volcano. The supposed signal for the supposed Theran eruption turned out to be no such thing, when someone finally bothered to look into it.
A big volcanic kaboom can have serious localized consequences, but in all of recorded history, only Tambora has scattered its effects over most of the world.
Also, the crater diameter is 6km, not 5 miles. It's really cool looking though. There are people who climb down into it, that's a good bucket list item, especially if it's right at the last item.