"Who'll Stop the Rain" by Creddence Clearwater Revival
In honor of six days of straight rain.
A thinly veiled reference to the War in Vietnam or is it about the deluge at Woodstock? I've heard both versions. Fogerty himself admits to writing it directly after Woodstock so it sounds like both are at least a bit true.
It's originally from the 1970 Creedence album "Cosmo's Factory", it is one of the songs now ingrained into American culture having appeared in numerous cover versions and films including one actually named after it.
Not to be confused with "Have you ever seen the rain".