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WanderNerd

Flight Reliability

WN 4139 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 4139 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

86%
Arrive within 15 minutes
1 min
Average arrival delay
1.1%
Cancelled
9 min early
Median arrival delay

Based on 185 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon88%(32 flights)
  • Tue79%(19 flights)
  • Wed89%(18 flights)
  • Thu85%(33 flights)
  • Fri91%(35 flights)
  • Sat80%(15 flights)
  • Sun87%(31 flights)
On-time by departure window
  • 6–9 AM93%(41 flights)
  • 9 AM–12 PM88%(41 flights)
  • 12–3 PM88%(48 flights)
  • 3–6 PM85%(26 flights)
  • 6–9 PM74%(27 flights)
On-time trend by month
81%
May

Jun 92% → May 81% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202592%26
July 202593%27
August 202590%19
September 202582%17
November 202579%14
February 202672%18
April 2026100%20
May 202681%26
Departures on time
80%
Diverted
0%
Flights flown
183
Months covered
12

Based on 185 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.