The 1883 volcanic eruption that likely influenced the red sky in “The Scream” was Krakatoa.
Krakatoa, a volcanic island in the Sunda Strait, erupted catastrophically in August 1883. The eruption injected enormous quantities of ash and aerosols into the atmosphere, producing unusually vivid red and orange sunsets in parts of the world for months afterward. Munch painted “The Scream” about a decade later, and some scholars have proposed that he remembered those atmospheric effects.
The idea fits Munch’s own account of seeing the sky turn “blood red” during an evening walk. The scene is generally identified with a road on Ekeberg overlooking Oslofjord, a landscape Munch knew well.
However, the Krakatoa explanation is not proven. Other interpretations point to nacreous clouds, which can occur at high latitudes, or to the psychological and personal circumstances surrounding the image. Munch was an expressive painter, so the sky may be an emotional transformation rather than a literal record of an eruption’s effects.