Talk:Ordinal date

Complete Equation?
How about a couple equations to calculate the ordinal date? The discussion is great but showing the most common equations would be useful. 153.90.200.9 (talk) 16:58, 3 January 2008 (UTC)

Arithmetic
The calculation is more elegantly done in integer arithmetic, as Zeller used. 82.163.24.100 (talk) 21:22, 1 October 2008 (UTC)

Fractional days
How are fraction dates rendered in the ordinal date system?

When on January 1 is it ordinal day #1?

If, like civil time, the day begins at midnight, what are the ordinal dates:
 * 1) At midnight when January 1 begins -- 0 or 1?
 * 2) At noon on January 1 -- 0.5 or 1.5?
 * 3) At midnight when January 2 begins -- 1.0 or 2.0?

Or, like a Julian day, does an ordinal date begin at noon, so:
 * 1) At midnight when January 1 begins, the ordinal date is -0.5
 * 2) At noon on January 1, the ordinal date is 1.0
 * 3) At midnight when January 2 begins, the ordinal date is 1.5

This question relates to the formulas in declination, where the value of 'N' is defined ambiguously as "the number of days elapsed since January 1." It doesn't say elapsed since when on January 1.

How might the concept of 'ordinal' day clarify the article on declination, where day numbers may be fractional? - Ac44ck (talk) 15:35, 2 April 2011 (UTC)


 * This page suggests Ordinal Day #1 begins at midnight on January 1:
 * http://www.decimaltime.hynes.net/p/fraction.html
 * as June 29 is day # 181 in a leap year; the fractional day is appended to the date number beginning at midnight.
 * There is no mention of zero or negative values for ordinal dates in the Wiki article ISO_8601. - Ac44ck (talk) 16:06, 2 April 2011 (UTC)

Number of Days in ISO Year
In several sources we may find, day numbering in ISO Year wouldn't be the same as in Gregorian Calendar. Though implementation of ISO 8601 seems to allow a common numbering in agreement with 365-366 days of Solar Year. In ISO week Year though, the number of weekdays per year may vary more. Is it standard provision or prospective from ISO 8601? Is it badly interpreteted? Though there seems to have nothing against 365-366 number of days per Gregorian Year in this norm, ISO Year regularly begins and finish a little after, its number of days per year would be 364 (7*52) or 371 (7*53). Which wouldn't be the same as is usually used - 365-366. Though I'm not sure it anticipates with the norm eventual developments. — Preceding unsigned comment added by JFG CA (talk • contribs) 21:01, 23 November 2011 (UTC)

Make 'Julian date' a disambiguation?
At present, Julian date redirects to Julian day. In the light of disruptive 'corrections' made to Julian calendar in the last few days, I have opened a discussion at Talk:Julian day to suggest an alternative. Please respond there. --John Maynard Friedman (talk) 21:50, 25 June 2019 (UTC)

February
Are this possible to add one more date on the February when its leap year? Because the days on February is less than 30 days. January, March, May, July, August, October, and December has 31 days and April, June, September, and November has 30 days and February is only 28 to 29 days. M Raisfath (talk) 22:31, 9 December 2022 (UTC) M Raisfath (talk) 22:40, 9 December 2022 (UTC) (edited)