This painting, usually called The Scream, said to represent the skies of Norway after the cataclysmic volcanic eruption of Krakatoa in 1883-4.
Although some scholars dispute this, I like to believe this explanation because the Krakatoa eruption is extremely interesting to me, and from what I have read about the colours of skies during that year, the explanation is entirely plausible.
In a page in his diary headed Nice 22.01.1892, Munch described his inspiration for the image as:
I was walking along a path with two friends – the sun was setting – suddenly the sky turned blood red – I paused, feeling exhausted, and leaned on the fence – there was blood and tongues of fire above the blue-black fjord and the city – my friends walked on, and I stood there trembling with anxiety – and I sensed an infinite scream passing through nature.
Der Schrei der Natur (The Scream of Nature), 1893
Oil, tempera and pastel on cardboard