Flight Reliability
WN 4020 · Southwest Airlines
This number covered several routes in this period.
One number, several routes.
Airlines reuse flight numbers, and WN 4020 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
- 71%
- Arrive within 15 minutes
- 15 min
- Average arrival delay
- 0.7%
- Cancelled
- 2 min
- Median arrival delay
Based on 282 historical flights. Data through May 2026.
The breakdown
- Mon64%(42 flights)
- Tue76%(29 flights)
- Wed64%(28 flights)
- Thu70%(46 flights)
- Fri67%(45 flights)
- Sat70%(30 flights)
- Sun81%(58 flights)
- 3–6 AM100%(11 flights)
- 6–9 AM100%(16 flights)
- 9 AM–12 PM91%(77 flights)
- 12–3 PM63%(113 flights)
- 3–6 PM—(6 flights)
- 6–9 PM44%(55 flights)
81%
May
Jun 48% → May 81% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 48% | 25 |
| July 2025 | 33% | 30 |
| October 2025 | 62% | 21 |
| February 2026 | 100% | 14 |
| March 2026 | 82% | 27 |
| April 2026 | 76% | 70 |
| May 2026 | 81% | 80 |
- Departures on time
- 64%
- Diverted
- 0.7%
- Flights flown
- 278
- Months covered
- 11
Keep nerding
Based on 282 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.