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WanderNerd

Flight Reliability

WN 3399 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 3399 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

63%
Arrive within 15 minutes
15 min
Average arrival delay
1.2%
Cancelled
4 min
Median arrival delay

Based on 171 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon72%(29 flights)
  • Tue89%(18 flights)
  • Wed70%(20 flights)
  • Thu56%(34 flights)
  • Fri42%(31 flights)
  • Sat63%(16 flights)
  • Sun65%(20 flights)
On-time by departure window
  • 6–9 AM96%(25 flights)
  • 12–3 PM66%(38 flights)
  • 3–6 PM56%(55 flights)
  • 6–9 PM52%(50 flights)
On-time trend by month
46%
May

Nov 90% → May 46% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
November 202590%10
December 202593%14
March 202663%24
April 202666%50
May 202646%56
Departures on time
57%
Diverted
0.6%
Flights flown
168
Months covered
10

Based on 171 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.