Beatles - Because Lyrics Meaning

While this song is pretty nuanced, there are some hints to help us understand its meaning. This song is about the fact that "there is nothing new under the Sun," and a person coming to terms with it.
The first indication of this is the airiness of the vocals, combined with the specific placement of the word 'because' so that the phrases tie in to each other, i.e. "because the wind is high, it blows my mind, because the wind is high." The other indication of this is that all three verses cover an element of nature that doesn't change; the Earth, the wind and the sky are all here to stay. But how do we know the message isn't so straightforward? We know from the line "because the sky is blue, it makes me cry." This indicates that the speaker wants the sky to be another color, a common literary metaphor for one's hope for an alternate reality that is all but impossible. The repeated emphasis on causality provided by the repetition of the title cements this idea. The melody is rather melancholic, but as mentioned earlier, the song is not one-sided, and the chorus points to love as one of the constants we'd rather not change.