Not really true. The exact moments of noon and midnight are ambiguous. The instant of midnight can equally be considered the end of one day or the beginning of another. ISO 8601 even permits midnight to be written as 24:00 where one is referring to the day just ended (although no clock would, in fact, display 24:00).
Similarly, the exact instant of noon can be considered as ending the morning or beginning the afternoon. That is why I never use 12 am or 12 pm, preferring the non-ambiguous 12 noon and 12 midnight. And that is why I overwhelmingly prefer the ISO 8601 standard. Please note that analog watches and clocks, although based on 12 hours, say nothing about am and pm, leaving interpretation up to the owner/user. By the way, why is going from 12:00:00 am to 12:00:01 pm any stranger than going from 11:59:59 am to 12:00:00 pm? They're equally strange and both arbitrary. Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator] >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >Behalf Of Carleton MacDonald >Sent: Thursday, January 01, 2004 12:36 >To: U.S. Metric Association >Subject: [USMA:28074] RE: Calendar, date and time > > >Except that won't work, because: > >The last moment of the day is 23:59:59, or 11:59:59 pm. >The first moment of the new day is 00:00:00, or 12:00:00 am. > >It would be very strange to go from 11:59:59 am to 12:00:00 am to >12:00:01 pm. > >cm > >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >Behalf Of Bill Potts >Sent: Thursday, January 01, 2004 15:18 >To: U.S. Metric Association >Subject: [USMA:28071] RE: Calendar, date and time > >Ah, I misunderstood you. > >Let's start again on that. I assumed you knew noon was at 12:00 >(as expressed in 24 hour time). > >Whether, in the am/pm scheme, noon is 12 am or 12 pm is an issue >with me, too. I've always regarded it as more logical to use 12 >am, with pm occurring (at 12:00:01) an instant later. 12 pm makes >sense for midnight, as that time is exactly 12 hours post meridiem >(i.e., past the sun's [nominal] highest point). However, common >practice is, illogically, the reverse of that. > >For this reason, if I find myself forced to use 12-hour time, I >refer to the two 12s as 12 noon and 12 mid (or 12 midnight), >avoiding the am/pm issue altogether. > >Bill Potts, CMS >Roseville, CA >http://metric1.org [SI Navigator] > > >>-----Original Message----- >>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >>Behalf Of Predrag Lezaic >>Sent: Thursday, January 01, 2004 09:43 >>To: U.S. Metric Association >>Subject: [USMA:28060] RE: Calendar, date and time >> >> >>So is 12:00 Noon - 12 AM or 12 PM? I constantly have problems with using >>this format on websites that use calendars. >> >>Predrag >> >>>I have the same problem as you with people who refer to 24-hour time as >>>military time. However, I have difficulty believing you don't know what >>>noon is. >> >
