We’re all aware of how vital marked and measured time is to guiding and structuring our days. How then do we treat it in precise and careful writing?<\/p>\n
We offered some guidelines in our updated April 2017 article\u00a0Writing Dates and Times<\/a>. We’ll expand on those here by delving deeper into the most recent editions of two of our primary style references,\u00a0The Chicago Manual of Style,<\/em> which commonly applies to formal publications (e.g., fiction and nonfiction books, textbooks, academic reports) and\u00a0The Associated Press Stylebook,<\/em> which often helps in advising journalistic and daily writing (e.g., newspapers, magazines, business marketing, and correspondence).<\/p>\n According to\u00a0CMOS,<\/em>\u00a0if we’re referring to times of day in even, half, and quarter hours, we would usually spell them out in writing. The number is always spelled out with\u00a0o’clock<\/em>.<\/p>\n Examples<\/strong><\/em><\/p>\n With the rain delay, the game probably won’t be over until at least ten o’clock.<\/em><\/p>\n The men’s open-gym basketball games usually end around a quarter of nine.<\/em><\/p><\/blockquote>\n When referencing exact times, we would use numerals, including zeros for even hours.<\/p>\n Examples<\/strong><\/em><\/p>\n The class is scheduled to begin at 7:00 this morning.<\/em><\/p>\n Our flight leaves at 8:25 tomorrow evening.<\/em><\/p><\/blockquote>\n For abbreviated day divisions,\u00a0CMOS<\/em>\u00a0recommends a.m. for\u00a0ante meridiem<\/em> (before noon) and p.m. for\u00a0post meridiem<\/em>\u00a0(after noon). These abbreviations also may be set in small caps with numerals.<\/p>\n Examples<\/strong><\/em><\/p>\n 9:23 p.m.<\/em><\/p>\n 7:47 a.m.<\/em><\/p>\n 6:00\u00a0A.M.<\/span><\/em><\/p><\/blockquote>\n It further points out that a.m. and p.m. should not be used with\u00a0morning, noon, afternoon, evening<\/em>,\u00a0night<\/em>, or\u00a0midnight<\/em>, nor should they be used with\u00a0o’clock.<\/em><\/p>\n Incorrect:<\/em> <\/strong>5:45 p.m. in the afternoon Incorrect:<\/em> <\/strong>six o’clock a.m. this morning For\u00a0midnight<\/em> and\u00a0noon, CMOS<\/em> advises not to use numbers except informally in an expression such as\u00a0twelve o’clock at night.<\/em>\u00a0Because\u00a0noon<\/em>\u00a0is technically 12:00 m. (meridies,<\/em> or mid-day), writing or saying\u00a012:00 p.m.<\/em>\u00a0(after noon) would be unclear as well as illogical. For certain references to\u00a0midnight,<\/em>\u00a0a double date might be included for clarity:\u00a0Richard was born at midnight, November 13\u201314.<\/em><\/p>\n AP<\/em> uses only figures for times and does not include them with\u00a0noon<\/em> and\u00a0midnight.<\/em>\u00a0It also omits zeros for even hours and sets day divisions in lowercase letters.<\/p>\n Examples<\/strong><\/em><\/p>\n Breakfast is at 9 a.m.<\/em><\/p>\n Lunch is at noon.<\/em><\/p>\n The next meeting is at 3:30 p.m.<\/em><\/p>\n The observatory program begins tonight at midnight.<\/em><\/p><\/blockquote>\n Like\u00a0CMOS, AP<\/em> directs to avoid such redundancies as\u00a010 a.m. this morning<\/em>\u00a0and\u00a010 p.m. tonight.<\/em>\u00a0It also cites\u00a0o’clock<\/em> constructions as acceptable but prefers that time be written with numerals and a.m. or p.m.<\/p>\n In scientific theory, Earth has 24 time zones, each a one-hour zone 15 degrees wide to indicate a one-hour difference in mean solar time. Politically, however, time zones are further influenced by how internal and international borders are drawn. Some of these zones have only 30- and 45-minute offsets, increasing the world’s total number of zones. The International Date Line also creates three more zones.<\/p>\n
\n<\/em>Correct:<\/em> <\/strong>5:45 p.m.<\/em>,\u00a05:45\u00a0P.M.<\/span><\/em>, or\u00a05:45 in the afternoon<\/em><\/p>\n
\n<\/em>Correct:<\/em> <\/strong>six o’clock this morning<\/em><\/p><\/blockquote>\nTime Zones<\/h2>\n