0:30 UTC - zero thirty UTC

Clock	Time	Spoken
24-hour clock	00:30	zero thirty, half past midnight, half past zero, thirty minutes past midnight, thirty minutes past zero, thirty minutes to one
12-hour clock	12:30 AM	twelve thirty am, half past midnight, half past twelve am, thirty minutes past midnight, thirty minutes past twelve am, thirty minutes to one am
Military	0030Z	zero-zero-three-zero hours, zero zero thirty hours

AM or A.M. - latin ante meridiem, meaning before midday, PM or P.M. - latin post meridiem, meaning after midday. Letter 'Z' in military time indicates ZULU Time Zone which is equivalent to UTC.