I had always thought the title of the song was July 7th, Sunny, since that's what the weather report uses for sunny (Hare).
BUT, 'hare' really means clear, and there's a line in the song:
Shichigatsu nanoka, hareta yozora kazu wo fuyasu hoshi
July 7th, clear night-sky number increase star(s)
The rest of the song is referring to a NIGHT SKY, too!
Which makes sense since 7/7 is the Tanabata Festival,
http://www.japan-guide.com/e/e2283.html
and of course the song references Vega and Altair.
I didn't realize that a NIGHT sky could be 'hare'; now this song makes a lot more sense
