This song is John Fogerty's take on the imminent departure of his brother Tom from the band, and the overall tension in the group at a time when they should have been enjoying their success. The line, "I want to know - have you ever seen the rain comin' down on a sunny day?" refers to Tom leaving while CCR was at its commercial zenith. The flip side of this single, "Hey Tonight," is John reassuring the band that all would go well despite the adversity.
Tom Fogerty left the group in early 1971, after this album was released. He released three solo albums before dying of tuberculosis in 1990. A fourth album, completed in 1988, was released posthumously.
According to John Fogerty, this song's meaning changed for him over time. Introducing the song at a 2012 show in Arizona, he said: "This song was originally written about a very sad thing that was going on in my life. But I refuse to be sad now. Because now this song reminds me of my little girl, Kelsy, and every time I sing it, I think about Kelsy and rainbows."
Fogerty added that this is his all-time favorite song, even though it's one he wrote himself.
Musically, this song was inspired by the group Booker T. & the MG's, whose most famous song is "Green Onions." They opened for Creedence Clearwater Revival before CCR recorded the Pendulum album. John Fogerty loved the sound of Booker T. Jones' Hammond organ, so he used it on some tracks for the album, including this one.
John Fogerty did almost all the overdubs for the band until the Pendulum album, when other members contributed. Their bass player Stu Cook played some of the piano on this track.
According to Stu Cook, this song and another track on the album, "Pagan Baby," were written and rehearsed from scratch during one recording session. "Pagan Baby" was done in one take."
This was used in the TV show Tour Of Duty, which was set in Vietnam during the war.