This is a seemingly slight song, somewhere between the reveries of "Cloudy" and the nonchalance of "Feelin' Groovy."
But there is a bit of history in the song, and trouble in the paradise it loosely describes.
"Sunny" was spun off of a song called "Lover Lover, Come Back," in which Simon was working with some Caribbean tropes. "Lover Lover" eventually became (what else?) "Mother and Child Reunion," and the leftover verses became "Was a Sunny Day," likewise an island-inflected tune.
The line "not a negative word was heard" seems to borrow both syntax and sense from the famous cowboy song "Home on the Range," where "seldom is heard/a discouraging word."
Newport News is a real town, in Virginia, and there is a Navy port there.
But our man Earl? Well, a band called The Cadillacs had a lead singer named Earl Carroll; his nickname was Speedo. In 1955, they recorded their biggest hit, "Speedo": "Well now, they often call me Speedo/ But my real name is Mr. Earl." (Speedo swimwear, incidentally, dates as far back as 1927!)
Our Earl exclusively dates a "girl" named Lorelei (her fidelity is not described). Her name is that of a mythical mermaid whose siren song leads men to their watery graves. The only other thing we know about her is that she peaked in high school, where she was a "queen," possibly of the prom or homecoming. Since her life is all downhill from here, she has "nothing, really, left to lose." And so, nothing to live for.
He is a sailor; she, a mermaid. She is going down, and it seems she is going to drag him down to the depths of her eventual depression with her.
But why dwell on that? Right now, it's "sunny" and cloudless, with Nature's "birdies" and mankind's "radio" singing in harmony.
The song is important, to the degree that it is, for its music more than its lyrics. It pulls from the 1950s rock that Simon loves, and yet it is another successful foray into the Caribbean songs that entrance him.
An autobiographical reading of the song might be: Simon, as the stolid Navy man, his transistor radio still plugged into the crew-cut sound of the past. The island music is the siren, the seductress that pulls him astray... but what a way to go.
(From a sheer quality standpoint, there is an exponential growth from the lumbering "Why Don't You Write Me" to the breezy "Was a Sunny Day"... and in just three years.)
Musical Note: The backing vocals are by sisters Maggie and Terre Roche. With the addition of another sister, Suzzy, they soon became The Roches, an excellent and quirky vocal ensemble; Simon produced their debut album.
Next song: Learn How to Fall