Outlook Calendar Week Numbers Do Not Match German Calendars by Default Outlook has the option of displaying week numbers from 1 to 52 to the left of each week in the little calendar, known as the Date Navigator. By default, the Date Navigator sets the first week of the year to Start onn Jan 1. This year this poses an inconsistency with the ISO standard that Germans use. The steps below first show how to have the week numbers displayed and displayed correctly. 1. From the menu bar, click Tools >> Options to open the Options dialog box. In that dialog box, click the Calendar Options... button 2. Under the Calendar work week section, select Monday for First day of week: and select First 4-day week for First week of year: 3. Next, make sure the Show week numbers in the Date Navigator check box is checked IF you want to see the week numbers in the Date Navigator 4. Look at your Data Navigator and confirm the week numbers show up. Notice the first week of 2005 "begins" 03-Januray-2005, which matches the German standard. More Information This week numbering scheme was introduced earlier by the ISO with the standard ISO 2015:1976 (Numbering of Weeks) and was repealed on 1 June 1988 with the imminent introduction of ISO 8601. The calendar defined in the ISO standards 2015 and 8601 is commonly referred to as the "ISO calendar". The ISO 8601 standard implicitly assumes that the ISO calendar corresponds with the Gregorian calendar (sect. 4.3.2.1 on pp. 6-7) and uses the same year number but as its length is defined to be an integral number of weeks, its beginning can deviate up to a few days from 1 January and its end likewise can deviate up to a few days from 31 December. On average, however, it remains in step with the Gregorian calendar. The week in the ISO calendar is defined (sect. 3.27-28 on p. 4) as: [a] time-interval of seven days, starting on a Monday and identified by its ordinal number within a calendar year. The numbering of the ISO calendar weeks is defined (sect. 4.3.2.2 on pp. 7-8) as: [...] the first calendar week of a year is the one that includes the first Thursday of that year and [...] the last calendar week of a calendar year is the week immediately preceding the first calendar week of the next year. Another way of stating the above rule is that the first week of the ISO calendar year is the earliest week that contains at least four days of the month of January. Likewise, the last week of the ISO calendar year is the last week that contains at least four days of the month of December. According to this rule the first week of the ISO calendar year can begin as late as 4 January and as early as 29 December of the previous year. Likewise, the last week of the ISO calendar year can end as early as 28 December and as late as 3 January of the following year. As described by http://www.phys.uu.nl/~vgent/calendar/isocalendar.htm |