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").
Economic nationalism While the coining of the term "
Eastern Time Zone The Uniform Time Act of 1966 ruled that daylight saving time would run from the last Sunday of April until the last Sunday in October in the United States.[3] The act was amended to make the first Sunday in April the beginning of daylight saving time as of 1987.[3] The Energy Policy Act of 2005 extended daylight saving time in the United States beginning in 2007. So local times change at 2:00 a.m. EST to 3:00 a.m. EDT on the second Sunday in March and return at 2:00 a.m. EDT to 1:00 a.m. EST on the first Sunday in November.[3] In Canada, the time changes as it does in the United States.[4][5]
Daylight saving time in the United States In the U.S., daylight saving time starts on the second Sunday in March and ends on the first Sunday in November, with the time changes taking place at 2:00 a.m. local time. With a mnemonic word play referring to seasons, clocks "spring forward, fall back"—that is, in springtime the clocks are moved forward from 2:00 a.m. to 3:00 a.m. and in fall they are moved back from 2:00 a.m. to 1:00 a.m. Daylight saving time lasts for a total of 34 weeks (238 days) every year, about 65% of the entire year.