Just noticed that Memorial Day is the earliest it can possibly be and Labor Day is the latest it can possibly be. Guess this is payback for the miserable winter we had 
Here in Canada, Victoria Day (the Monday following the weekend before Memorial Day weekend) is also early. And Labo(u)r Day is on my birthday this year.
The Victoria Day weekend is the traditional time to open the cottage for the summer (and push the half-melted ice floes out of the way so you can dive down and pull the intake valve end of the water pipe out of the mud it’s sunk into over the winter).
I see. I wouldn’t know, as my family is not wealthy enough to own a cottage. But it makes sense that it’s sort of considered the beginning of summer, and also it’s amusing that it’s slightly before the American date considered the beginning of summer, because we all know Canada is such a cold place. 
Here in Northern Ohio we’re already working on a longer Summer. We’ve had days in early May that have set/tied heat records. It’s all about the extremes.
Tangential question:
How long are American businesses expected to fly their flags at power-saving levels for Memorial Day? I saw flags half way up in several places last week, and asked the manager at one business why the flags were like that. He said it was due to the up-coming Memorial Day.
Flags are at half-staff for two weeks or more before Memorial Day? How come I never noticed that before?
Winter is coming. /Jon Snow
Indeed. This coming June will be one second longer than last year (Leap Second - What is it?). I plan on sleeping in.
I judge seasonal length by weather. I’m pretty sure meteorology doesn’t pay attention to the calendar.
You know nothing.
Because it’s wrong.
On 5/15, flags were at half-mast for “Peace Officers Remembrance Day”. But nothing since.