WN4156
WN4156 (Southwest Airlines) is a multi-stop service on 21 routes, busiest Chicago to Miami. Of 334 departures recorded from October 2024 to July 2026, 78.3% left on time, according to the US BTS.
- On-time departures78.3%of 334 flights
- Average delay9.2 min
- July 202631▲ 675.0%vs July 2025
- Cancelled0.6%
- Legs flown under this number21
Recorded departures by month
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods17 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 26 | 8 | ▼ 69.2% |
| February | 26 | 8 | ▼ 69.2% |
| March | 30 | 27 | ▼ 10.0% |
| April | 25 | 5 | ▼ 80.0% |
| May | 25 | 1 | ▼ 96.0% |
| June | 7 | 27 | ▲ 285.7% |
| July | 4 | 31 | ▲ 675.0% |
| August | 1 | – | – |
| September | – | – | – |
| October | – | – | in progress |
| November | 15 | – | – |
| December | 12 | – | – |
| Year to date (Jan–Jul) | 143 | 107 | ▼ 25.2% |
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 periods17 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 80.8% | 100.0% | ▲ 23.8% |
| February | 88.5% | 25.0% | ▼ 71.7% |
| March | 93.3% | 73.1% | ▼ 21.7% |
| April | 84.0% | 60.0% | ▼ 28.6% |
| May | 76.0% | 0.0% | ▼ 100.0% |
| June | 71.4% | 96.3% | ▲ 34.8% |
| July | 100.0% | 90.3% | ▼ 9.7% |
| August | 100.0% | – | – |
| September | – | – | – |
| October | – | – | in progress |
| November | 53.3% | – | – |
| December | 16.7% | – | – |
| Year-to-date average (Jan–Jul) | 84.9% | 63.5% | ▼ 25.1% |
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 periods17 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 1 | – |
| February | 0 | 0 | – |
| March | 0 | 1 | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | – | – | – |
| October | – | – | in progress |
| November | 0 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 0 | 2 |
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 99.4% 332
- Cancelled 0.6% 2
Share of all recorded flights in the period, all legs. · Oct 13, 2024 → Jul 31, 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 |
|---|---|---|---|---|
| MDW MIA Chicago Midway International Airport – Miami International Airport | 1,905 | 8.0 min | 80.3% | 81 |
| BOS DEN Boston Logan International Airport – Denver International Airport | 2,816 | 1.8 min | 93.1% | 58 |
| OGG HNL Kahului International Airport – Daniel K. Inouye International Airport | 162 | -4.3 min | 100.0% | 32 |
| SAT MCO San Antonio International Airport – Orlando International Airport | 1,672 | 0.7 min | 93.8% | 32 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 10 | 10 | 90.0% | 0 |
| November 2024 | 24 | 24 | 75.0% | 0 |
| December 2024 | 22 | 22 | 72.7% | 0 |
| January 2025 | 26 | 26 | 80.8% | 0 |
| February 2025 | 26 | 26 | 88.5% | 0 |
| March 2025 | 30 | 30 | 93.3% | 0 |
| April 2025 | 25 | 25 | 84.0% | 0 |
| May 2025 | 25 | 25 | 76.0% | 0 |
| June 2025 | 7 | 7 | 71.4% | 0 |
| July 2025 | 4 | 4 | 100.0% | 0 |
| August 2025 | 1 | 1 | 100.0% | 0 |
| November 2025 | 15 | 15 | 53.3% | 0 |
| December 2025 | 12 | 12 | 16.7% | 0 |
| January 2026 | 8 | 7 | 100.0% | 1 |
| February 2026 | 8 | 8 | 25.0% | 0 |
| March 2026 | 27 | 26 | 73.1% | 1 |
| April 2026 | 5 | 5 | 60.0% | 0 |
| May 2026 | 1 | 1 | 0.0% | 0 |
| June 2026 | 27 | 27 | 96.3% | 0 |
| July 2026 | 31 | 31 | 90.3% | 0 |