The red sunlight symbolizes the mass amounts of blood spilled during the war. It is not clear what war Poe is referring too, however at the time of the writing of this poem both the war of 1812 and the wars of Spanish American independence were under way.
I am all of the above. I love the rain and moon that I can feel them before they make an appearance. The night is my sanctuary and I just love thunder and lightning. Soothing >> I am a Pluviophile and a Selenophile.