WN4243
WN4243 (Southwest Airlines) is a multi-stop service on 16 routes, busiest St Louis to San Francisco. Of 305 departures recorded from October 2024 to July 2026, 60.5% left on time, according to the US BTS.
- On-time departures60.5%of 305 flights
- Average delay20.6 min
- July 202617▼ 45.2%vs July 2025
- Cancelled0.3%
- Legs flown under this number16
Recorded departures by month
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods16 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 3 | 31 | ▲ 933.3% |
| February | 2 | 28 | ▲ 1,300.0% |
| March | 1 | 24 | ▲ 2,300.0% |
| April | – | 21 | – |
| May | 2 | 23 | ▲ 1,050.0% |
| June | 26 | 16 | ▼ 38.5% |
| July | 31 | 17 | ▼ 45.2% |
| August | 19 | – | – |
| September | 17 | – | – |
| October | – | – | in progress |
| November | – | – | – |
| December | 18 | – | – |
according to the US BTS · October 2024 → July 2026
On-time departures by month
Months without data are left blank.
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods16 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 0.0% | 54.8% | – |
| February | 100.0% | 57.1% | ▼ 42.9% |
| March | 100.0% | 91.7% | ▼ 8.3% |
| April | – | 57.1% | – |
| May | 100.0% | 50.0% | ▼ 50.0% |
| June | 53.9% | 37.5% | ▼ 30.4% |
| July | 61.3% | 41.2% | ▼ 32.8% |
| August | 57.9% | – | – |
| September | 76.5% | – | – |
| October | – | – | in progress |
| November | – | – | – |
| December | 72.2% | – | – |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
Months without data are left blank.
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
Months without data are left blank.
The most recent periods16 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 0 | – |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | – | 0 | – |
| May | 0 | 1 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | – | – | in progress |
| November | – | – | – |
| December | 0 | – | – |
according to the US BTS · October 2024 → July 2026
This is a historical record of departures already flown, not a forecast for your flight.
Several legs: the headline figure averages all of them. See the leg table.
Cancellation share
- Not cancelled 99.7% 304
- Cancelled 0.3% 1
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 29, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
4| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| STL SFO St. Louis Lambert International Airport – San Francisco International Airport | 2,786 | 22.8 min | 59.0% | 61 |
| DEN MSP Denver International Airport – Minneapolis–Saint Paul International Airport / Wold–Chamberlain Field | 1,092 | 20.1 min | 55.2% | 58 |
| SJC LAS Mineta San Jose International Airport – Harry Reid International Airport | 620 | 29.7 min | 46.2% | 40 |
| SBA LAS Santa Barbara Municipal Airport – Harry Reid International Airport | 464 | 11.5 min | 65.6% | 32 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 10 | 10 | 80.0% | 0 |
| November 2024 | 5 | 5 | 100.0% | 0 |
| December 2024 | 11 | 11 | 45.5% | 0 |
| January 2025 | 3 | 3 | 0.0% | 0 |
| February 2025 | 2 | 2 | 100.0% | 0 |
| March 2025 | 1 | 1 | 100.0% | 0 |
| May 2025 | 2 | 2 | 100.0% | 0 |
| June 2025 | 26 | 26 | 53.9% | 0 |
| July 2025 | 31 | 31 | 61.3% | 0 |
| August 2025 | 19 | 19 | 57.9% | 0 |
| September 2025 | 17 | 17 | 76.5% | 0 |
| December 2025 | 18 | 18 | 72.2% | 0 |
| January 2026 | 31 | 31 | 54.8% | 0 |
| February 2026 | 28 | 28 | 57.1% | 0 |
| March 2026 | 24 | 24 | 91.7% | 0 |
| April 2026 | 21 | 21 | 57.1% | 0 |
| May 2026 | 23 | 22 | 50.0% | 1 |
| June 2026 | 16 | 16 | 37.5% | 0 |
| July 2026 | 17 | 17 | 41.2% | 0 |