3Standards for dates
We follow The Chicago Manual or "ISO 8601" standards for writing dates. The examples below present guidelines for dating content, either digitally or in print, and are likely to satisfy most requirements.
3.1Print or web-published dates
In most print or web-published documents, we use the U.S. English format for writing dates. This format dictates that the month is stated before the day. The table below shows how these dates should be formatted.
| Year only | YYYY | 2013 |
|---|---|---|
| Year and month | Month, YYYY | April, 2013 |
| Month and day | Month DD | April 5 |
| Complete date | Month DD, YYYY | April 5, 2013 |
| Complete named date | Month DD, YYYY, Name | May 17, 2013, Constitution Day |
In a sentence, the year in a date should be set off by commas on both sides–even if it is used as an adjective. For example:
Opera for Android Beta 3 was released March 21, 2013, and includes a number of fixes.
Avoid a zero before a single-digit date (e.g., "06") or ordinal numbers (e.g., "6th") to indicate the day. Never abbreviate the month, unless absolutely necessary due to space considerations.
3.2ISO standards for digital content
When labeling digital content, the Opera Style Guide recommends guidelines extracted from "ISO 8601", the international standard for the representation of dates and times. A particular problem with "ISO 8601" is that it allows the century to be omitted from years. It also describes a very large number of date and time formats. To reduce the scope for error, we restrict the supported formats here.
The basic idea is to present time with the most broad information first, leading to the most specific information last. This method helps logical sorting of dates.
The table below profiles six levels.
| Year only | YYYY | 2013 |
|---|---|---|
| Year and month | YYYY-MM | 2013-04 |
| Complete date | YYYY-MM-DD | 2013-04-25 |
| To the min. | YYYY-MM-DDThh:mmTZD | 2013-04-25T12:30+01.00 |
| To the sec. | YYYY-MM-DDThh:mm:ssTZD | 2013-04-25T12:30:22+01.00 |
| Fraction of sec. | YYYY-MM-DDThh:mm:ss.sTZD | 2013-04-25T12:30:22.5+01.00 |
Exactly the components shown in the table must be present, with their exact punctuation. Note that the "T" appears literally in the string, to indicate the beginning of the time element, as "ISO 8601" specifies.
Always use four digits for year and two digits for month, day, hour, minute, and second. Use one or more digits for a decimal fraction of a second.
Times are assumed to be expressed in local time if no time zone is used. "TZD" is the time zone designator. A time zone offset of "+hh:mm" indicates that the date and time uses a local time zone, which is "hh" hours and "mm" minutes ahead of Coordinated Universal Time (UTC). A time zone offset of "-hh:mm" indicates that the date and time uses a local time zone, which is "hh" hours and "mm" minutes behind UTC.
For example, "2002-06-05T08:15:30-05.00" would be interpreted as June 5, 2002, 8:15:30 AM, U.S. Eastern Standard Time. If you were to write the same moment in Oslo's local time, it would appear as "2002-06-05T13:15:30+01.00".
3.3Press release dates in AP style
In press releases, the Associated Press Stylebook format must be used. When a month is used with a specific date, Jan., Feb., Aug., Sept., Oct., Nov., and Dec. should be abbreviated. For example:
Opera launched the beta version on Feb. 21, 2013, and is set to release the final product June 22.
When months are used without a numbered day–either by themselves or accompanied only by a year–they should not be abbreviated. For example:
The fastest browser on earth, Opera 11.0, was released in December.
Like internal documentation or web-published materials, dates in press releases should not use ordinals (–st, –nd, –rd, or –th), or a zero before a single digit day.