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Flight Reliability

WN 3840 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 3840 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

70%
Arrive within 15 minutes
8 min
Average arrival delay
0.9%
Cancelled
0 min
Median arrival delay

Based on 212 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon58%(26 flights)
  • Tue83%(29 flights)
  • Wed74%(27 flights)
  • Thu58%(26 flights)
  • Fri65%(31 flights)
  • Sat78%(36 flights)
  • Sun69%(35 flights)
On-time by departure window
  • 6–9 AM100%(13 flights)
  • 9 AM–12 PM56%(55 flights)
  • 12–3 PM—(8 flights)
  • 3–6 PM63%(51 flights)
  • 6–9 PM74%(66 flights)
  • 9 PM–12 AM82%(17 flights)
On-time trend by month
77%
May

Jun 100% → May 77% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 2025100%20
July 202574%19
October 202563%43
November 202584%19
December 202571%17
March 202668%25
April 202637%30
May 202677%31
Departures on time
69%
Diverted
0%
Flights flown
210
Months covered
10

Keep nerding

Based on 212 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.