Wrong week number in ansible gather_facts

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1

gather_facts: true in playbook

The datetime info is:

    "ansible_date_time": {
      "year": "2025",
      "month": "04",
      "weekday": "Monday",
      "weekday_number": "1",
      "weeknumber": "17",
      "day": "28",
      "hour": "05",
      "minute": "26",
      "second": "21",
      "epoch": "1745817981",
      "epoch_int": "1745817981",
      "date": "2025-04-28",
      "time": "05:26:21",
      "iso8601_micro": "2025-04-28T05:26:21.207762Z",
      "iso8601": "2025-04-28T05:26:21Z",
      "iso8601_basic": "20250428T052621207762",
      "iso8601_basic_short": "20250428T052621",
      "tz": "UTC",
      "tz_dst": "UTC",
      "tz_offset": "+0000"
    },

According to Ansible, we’re living in week 17

ncal -w results in:

    April 2025
Su     6 13 20 27
Mo     7 14 21 28
Tu  1  8 15 22 29
We  2  9 16 23 30
Th  3 10 17 24
Fr  4 11 18 25
Sa  5 12 19 26
   14 15 16 17 18

So week 18. Outlook also says ‘week 18’.

Is this a bug, a known feature, or are all my other systems off by a week?

2

There is not the week number. There are multiple different systems that compute a week number, see Week - Wikipedia. Ansible uses a different system than your Outlook, apparently.

(See also GitHub · Where software is built)

3

Helping @felixfontein out, the link you have seems to be slightly off. Try this link!