Which one is correct?

Question

It's a hump day.
It's the hump day.
It's hump day.
It's Hump Day.

Among these, which one is correct
if you are not talking about specific Wednesday?

Answer 1

"hump day", as in: "Thank goodness it's hump day and the weekend is in sight."

"a hump day", as in: "I remember the meeting being on a hump day."

"the [....] hump day", as in: "Our cargo ship went down on the last hump day in March." (a bit weird, but there you go!)

No cap 'H', unless it 'hump' begins the sentence.

Answer 2

It's Hump Day - that one implies that you are speaking about Wednesday

It's hump day - this implies that you are referring to a certain day that has been dsignated (by people at work, for example) that it's the middle of the week

It's a hump day - implies that the day is not normally designated as a hump day....maybe it was decided spontaneously

It's the hump day - this one implies that one day has been designated as such and that it occurs regularly. I'd have to choose this one.