Who said
“Is there anything so rare as a day in June”
Dats it 
I think you got the quote wrong, try this.
http://www.google.com/search?hl=en&q="so+rare+as+a+day+in+June"
And what is so rare as a day in June?
Then, if ever, come perfect days;
Then Heaven tries the earth if it be in tune,
And over it softly her warm ear lays.
James Russell Lowell
and boy, was he ever spot on.
Lessee . . . 110° yesterday 111° predicted today, currently 104° at the airport. I’m guessing he didn’t live here.
Early May, maybe mid to late April is our pleasant time here.
I remember this poem being a key piece of evidence in one of those Alfred Hitchcock kids’ mysteries collections from the early 1970s. It’s always stuck with me.
Me too! “Rare stamp” was the answer, referring to the British Guiana 1c magenta, and letting the young protagonist know that “GUIANA,” spelled backwards, was the combination to the safe in which he was locked. He was able to get out early and the bad guy was caught.
That’s it! It’s coming back to me now. Wasn’t the story named something like “The Three Mice,” from the phrase “my solicitor,” which the rich old stamp collector was trying to say over the mansion’s intercom after he got shot (“I suspect my sssssssssss…”)?
Pogo Possum (or Churchy LaFemme) once said it, IIRC. Albert countered that the while the 29th of Feb is much rarer, it can’t hold a candle to the 42nd of April