Weekmark

Calendar week · ISO 8601

Week 39, 2025

Monday 22 September – Sunday 28 September 2025

  1. Mon22Sep
  2. Tue23Sep
  3. Wed24Sep
  4. Thu25Sep
  5. Fri26Sep
  6. Sat27Sep
  7. Sun28Sep
ISO week
2025-W39
Copy as
CW39 (22–28 Sep)
Quarter
Q3 2025
Weeks in 2025
52
US week number
39

Week 39 is also written KW 39 (Kalenderwoche) or CW 39. ISO weeks start on Monday, and week 1 is the week with the year’s first Thursday. US calendars start weeks on Sunday and count the week with 1 January as week 1, so they give Monday 22 Sep to Saturday 27 Sep the same number: week 39.