Yes, zero to do with weather, wind, etc. Weather across the CONUS on Sunday Oct 31st, 2021 is about as nice as it can be, regardless of the season.
KDFW Weather Observations - rolling 120 hours
Date/Cancelled/Delayed 10-31-2021/ (as of 6pm CDT) #974/35% / #355/12%
Date/Cancelled/Delayed 10-30-2021/ #542/20% / #404/14%
Date/Cancelled/Delayed 10-29-2021/ #232/7% / #172/7%
Date/Cancelled/Delayed 10-28-2028/ #20/--- / #331/12%
A "delayed" flight is anything arriving beyond 15 minutes of scheduled arrival time.
(above as reported by
https://flightaware.com/live/cancelled) Excuse the funky formatting; FT software was never intended to be pretty.
The FAA's rules regarding "duty time in a month", etc. for crews is based on a rolling 28 days (not calendar months). It's been like that for years. Whether or not the individual airlines & their respective unions still choose to schedule & operate by a calendar month is....up to them.
A more granular view worthy of note is the percentage of cancellations by individual AA hub airport so far today:
DFW 19%
CLT 19%
MIA 13%
ORD 6%
PHX 10%
With another 5-6 hours of the reporting day yet to go, these figures will obviously need to shake-out a bit. But wow....