12:27 am UTC - twelve twenty-seven am UTC

Clock	Time	Spoken
12-hour clock	12:27 AM	twelve twenty-seven am, twenty-seven minutes past midnight, twenty-seven minutes past twelve am, thirty-three minutes to one am
24-hour clock	00:27	zero twenty-seven, twenty-seven minutes past midnight, twenty-seven minutes past zero, thirty-three minutes to one
Military	0027Z	zero-zero-two-seven hours, zero zero twenty-seven 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.