Power Automate (WDL) function

dayOfWeek — Power Automate (WDL) function reference

Day-of-week number.

Syntax

wdl

dayOfWeek(timestamp)

wdl

dayOfWeek(utcNow())

→ 0 (Sun) to 6 (Sat)

wdl

or(equals(dayOfWeek(utcNow()), 0), equals(dayOfWeek(utcNow()), 6))

→ true on a weekend

wdl

if(equals(dayOfWeek(item()?['DueDate']), 1), 'Monday deadline', 'Other')

→ "Monday deadline" / "Other"

Sunday is 0 and Saturday is 6 — this is fixed and not locale-sensitive, unlike formatDateTime() day names which do respect locale.
No timezone conversion is applied first — if the timestamp is UTC and your business day boundary is local, convert with convertFromUtc() before calling dayOfWeek().

From Date & time