„Kalenderwoche“

[Raketenwilli]

Eine gute Quelle für Fragen dieser Art ist Markus Kuhn.

Zitat:

Week 01 of a year is per definition the first week that has the Thursday in this year, which is equivalent to the week that contains the fourth day of January. In other words, the first week of a new year is the week that has the majority of its days in the new year. Week 01 might also contain days from the previous year and the week before week 01 of a year is the last week (52 or 53) of the previous year even if it contains days from the new year. A week starts with Monday (day 1) and ends with Sunday (day 7).

Das bezieht sich auf die Norm ISO 8601, die in Europa gilt. (In den U.S. gilt der Sonntag als erster Tag der Woche.)

Hm. Genau das hab ich nachgelesen, bevor ich die Behauptung über PHP::date("W") eingefügt habe.