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Flight Reliability

WN 1231 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 1231 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

73%
Arrive within 15 minutes
9 min
Average arrival delay
1.1%
Cancelled
4 min early
Median arrival delay

Based on 448 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon58%(62 flights)
  • Tue77%(62 flights)
  • Wed86%(64 flights)
  • Thu75%(69 flights)
  • Fri82%(62 flights)
  • Sat74%(78 flights)
  • Sun53%(45 flights)
On-time by departure window
  • 6–9 AM96%(55 flights)
  • 9 AM–12 PM89%(46 flights)
  • 12–3 PM67%(75 flights)
  • 3–6 PM69%(109 flights)
  • 6–9 PM71%(143 flights)
  • 9 PM–12 AM29%(14 flights)
On-time trend by month
87%
May

Jun 57% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202557%42
July 202576%45
August 202591%34
September 202593%30
October 202564%78
November 202554%26
December 202563%41
January 202669%29
February 202681%26
March 202680%30
April 202683%30
May 202687%31
Departures on time
66%
Diverted
0.2%
Flights flown
442
Months covered
12

Keep nerding

Based on 448 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.