I'm looking forward to Zero Dark Thirty, and curious to know where the title comes from. Does anyone know?
Director Kathryn Bigelow explains the significance of the title:
It’s a military term for 30 minutes after midnight, and it refers also to the darkness and secrecy that cloaked the entire decade long mission.
And this review reveals:
...the raid that has Navy SEALs striking Bin Laden's Pakistan compound [happens] at half past midnight (the coded "Zero Dark Thirty").
According to the handbook Air Force 101 - Military Time the time between 00:01h and 05:59h can be refered to as "oh-dark-thirty".
And according to this military website "oh-dark-thirty" is equivalent to "zero-dark-thirty" and "zero-dark-hundred / oh-dark-hundred".
It's humourous military slang for the small hours of the night, when you'd rather be asleep than on duty.
In addition to zero dark thirty, another term is zero dark hundred, or more commonly oh dark hundred, which, according to a qualified paratrooper (Army, Airborne) and former soldier (MI, Armor, Engineer):
In military (US) slang that period [between midnight and dawn] is referred to as "oh-dark hundred" or sometimes "zero-dark hundred". On the 24-hour clock the hours before 10 am start with a 0; so 1:00 am is 0100 and said as oh-one-hundred and so forth. Thus oh-dark hundred is anytime after midnight while it is still dark:
"The woke us up at oh-dark-hundred and ran us thru the obstacle course." Meaning they woke us up in the wee hours of the morning before daylight.
Close but not exactly Simon.
Being in the Military I have rarely heard "Zero Dark Thirty" it is almost always pronounced as "Oh Dark Thirty," "Oh Dark Hundred" or mainly "Oh Dark Stupid". It refers to simply the 0 before the time in 24 hour time. Example: 0100, 0230, 0450 would all be pronounced in the above fashion and NOT by "One Dark Hundred" or "Two Dark Thirty". It is simply military slang or humour regarding getting woken up in the dark hours of the morning.
So it does not specifically mean 0030.
Turns out it's answered in the trivia section of the IMDb entry:
"0 dark 30" is a term commonly used by the military to refer to a non-specific time when it is dark outside, either very late or very early. However, the prevailing pronunciation is "oh dark thirty".