when does the time change from am to pm
Midnight While computers and digital clocks display "12:00 a.m." and "12:00 p.m.", those notations provide no clear and unambiguous way to distinguish between midnight and noon. Strictly speaking, it is actually incorrect to use "a.m." and "p.m." when referring to noon or midnight (12:00). The abbreviation a.m. stands for ante meridiem or before noon and p.m. stands for post meridiem or after noon. Since noon is neither after noon nor before noon, and midnight can equally be twelve hours before and after noon, neither abbreviation is correct (although the length of the error is determined by the smallest unit of time — 12:00:01 p.m. would be the correct notation for "1 second after noon").