A brief history of time-keeping

It is April 4, 2004, at least in those places that follow the standard Gregorian 12-month calendar notation and time-keeping, which is virtually everywhere.

A number of other calendars are observed around the world. For example, A.D. 2004 is 5765 in the Jewish calendar and 1425 in the Islamic calendar, but in communications outside those countries, the Gregorian calendar is the common record.

When it comes to digital notation of time, however, 4/4/4 (or 04/04/04 if you include the zeros) is one of only a dozen dates each century that cannot be confused, no matter where you might be.

On all other dates, when the digits used to designate the month and day are not the same, there's potential for major misunderstandings.

While you might expect that, with minuscule variations, the passage of time is constant around the planet, not so for its notation.

Experienced international travelers know that in many countries, when the date is notated either in script or in digits, the day of the month precedes the month and the year, rather than having the month first as is done in the United States.

Few people will make a mistake when they see a calendar listing for 5 April, 2004. However, you can see how problems might arise if you make a reservation in a Paris hotel for 4/5, thinking April 5, while the person at the other end of the communications link thinks you are asking for a May 4 booking.

Similar misunderstandings can arise in many other situations, from calculating dates for visa requests and passport expirations, to tracking expiration dates for medicines and perishable foods purchased overseas. Even more of an issue is information that is printed in brochures and on Web sites.

What is particularly troubling is that these misunderstandings can occur without either party being aware of the problem until it's too late to make a simple correction.

That is why when you research plans or make reservations for a trip overseas, you must understand how time is kept where the information originates. Accurate information is even more crucial now that many people are making their own travel plans rather than relying on travel agents. A simple misunderstanding can cause significant problems, especially when so many deposits are nonrefundable.

In general, in addition to the United States, countries that observe the mm/dd/yyyy format include the nations of Central and Latin America, except for Brazil and Argentina, which follow the European convention of dd/mm/yyyy. Most Canadians follow the U.S. system, except Quebec, which has decided to adopt a third system of notation, the International Date Format, which is yyyy/mm/dd.

In most countries of Western Europe and Britain, however, the day precedes the month, except for Italy, Switzerland and Norway, which follow the U.S. lead.

When it comes to notating time, Russia marches along with Western Europe, while Sweden and other Eastern European nations such as Poland, Hungary, the Czech Republic and the former Yugoslav republics use the International Date Format, as do China and Japan.

Actually, the geographic differences in time don't stop with the date. The formats for notating the time of day also vary.

Civilians in nations throughout the Western Hemisphere and United Kingdom generally follow a 24-hour clock, which is divided into two 12-hour segments, ante meridian and post meridian (a.m. and p.m.), the "meridian" being noon, supposedly when the sun is highest in the sky.

Although foreign clock faces are still divided into 12-hour segments, timekeeping in most other nations adheres to the "military" standard, where the afternoon and evening hours run from 13 to 24, which is midnight. Thus, the time we call 3:47 p.m. here would be 15:47 there.

Even the punctuation of time differs geographically.

Although everyone notes the time of day with hours first, then minutes and seconds, most countries separate them with a colon. Italy and Sweden use a period; Switzerland, a comma.

An international standard

A lot of these problems could be avoided if all nations adopted ISO 8601, the recommended international standard that designates Gregorian calendar dates in a ccyy-mm-dd format. The cc is the century (the thousands and hundreds digits, as opposed to the actual century), yy is the year, mm is the month of the year between 01 (January) and 12 (December), and dd is the day of the month between 01 and 28 or 29 or 30 or 31, depending on length of month and whether it is a leap year.

ISO 8601 proponents say this format, in addition to being exact, presents the components of time in order of descending magnitude, from centuries to seconds. They say astronomers have been following this system for centuries, and it is already used in a half-dozen countries, including China.

Unfortunately, putting the year first is more clumsy for common usage, providing the least changing information first. People almost always know what the year and month are. It is the day that is most often in question, which begs an argument for putting the day first.

Given how difficult it is for a nation to change its timekeeping methods, it's not likely that these differences will be ironed out any time soon. The best anyone can do is to be aware of them and take them into consideration when conducting foreign communications.

So to make accurate choices, before assessing any foreign date information, ask yourself some questions. Where is the Web site you are visiting based? Is the writer of that brochure, e-mail or letter from the United States, Europe, Japan? Could the author be of one of these nationalities living in a foreign country who became confused and got the numeric fields in an order different from what they intended? Though seemingly far-fetched, any of these possibilities might have a dramatic impact on your travel plans.

A partial listing of other counties' time-keeping formats can be found at fd-doc.sourceforge.net/spec/country.html.