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WanderNerd

Flight Reliability

WN 3856 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 3856 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

67%
Arrive within 15 minutes
14 min
Average arrival delay
1.3%
Cancelled
3 min
Median arrival delay

Based on 297 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon78%(45 flights)
  • Tue67%(33 flights)
  • Wed76%(33 flights)
  • Thu63%(46 flights)
  • Fri57%(47 flights)
  • Sat68%(34 flights)
  • Sun65%(54 flights)
On-time by departure window
  • 6–9 AM90%(29 flights)
  • 9 AM–12 PM(3 flights)
  • 12–3 PM61%(98 flights)
  • 3–6 PM73%(22 flights)
  • 6–9 PM64%(136 flights)
  • 9 PM–12 AM(4 flights)
On-time trend by month
54%
May

Jun 76% → May 54% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202576%38
July 202563%41
October 202567%30
November 202556%16
January 202692%25
February 202682%27
March 202653%30
April 202676%33
May 202654%35
Departures on time
61%
Diverted
0.3%
Flights flown
292
Months covered
12

Based on 297 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.