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WanderNerd

Flight Reliability

WN 3959 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 3959 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

75%
Arrive within 15 minutes
6 min
Average arrival delay
3.9%
Cancelled
0 min
Median arrival delay

Based on 153 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon71%(14 flights)
  • Tue77%(22 flights)
  • Wed81%(21 flights)
  • Thu69%(16 flights)
  • Fri86%(21 flights)
  • Sat48%(21 flights)
  • Sun84%(32 flights)
On-time by departure window
  • 6–9 AM96%(23 flights)
  • 9 AM–12 PM91%(55 flights)
  • 12–3 PM42%(31 flights)
  • 3–6 PM(8 flights)
  • 6–9 PM(9 flights)
  • 9 PM–12 AM57%(21 flights)
On-time trend by month
84%
May

Dec 60% → May 84% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
December 202560%10
February 2026100%17
March 202633%21
April 202688%34
May 202684%32
Departures on time
70%
Diverted
0%
Flights flown
147
Months covered
11

Based on 153 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.