It doesn’t take much to darken the skies. In 1991 gulf war, the oil well fires blocked the sun quite well. I saw it. So Ehat you say about volcanoes is plausible.
In the year or two after Pinatubo in 1991 there were severe climate influences. In the US north east, my brother in upper New York told me about the severe ice storm that deposited more than an inch of ice on branches and rows of broken trees up and down the highways. Googling “severe weather effects after Pinatubo 1991” yielded the links listed below. There were others about effects in various parts of the world.
https://earthobservatory.nasa.gov/images/1510/global-effects-of-mount-pinatubo
https://pubs.usgs.gov/pinatubo/self/ [a detailed scientific article with interesting details near the bottom]
https://en.wikipedia.org/wiki/Volcanic_winter [major volcanic events]