WN4120
WN4120 (Southwest Airlines) is a multi-stop service on 24 routes, busiest Chicago to Denver. Of 429 departures recorded from October 2024 to July 2026, 68.0% left on time, according to the US BTS.
- On-time departures68.0%of 429 flights
- Average delay17.7 min
- July 202645▲ 181.3%vs July 2025
- Cancelled2.3%
- Legs flown under this number24
Recorded departures by month
All legs under this number combined; see the leg table.
The most recent periods19 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 27 | 1 | ▼ 96.3% |
| February | 28 | 3 | ▼ 89.3% |
| March | 4 | 31 | ▲ 675.0% |
| April | 26 | 7 | ▼ 73.1% |
| May | 34 | 1 | ▼ 97.1% |
| June | 21 | 39 | ▲ 85.7% |
| July | 16 | 45 | ▲ 181.3% |
| August | 25 | – | – |
| September | 26 | – | – |
| October | 31 | – | in progress |
| November | 3 | – | – |
| December | 6 | – | – |
| Year to date (Jan–Jul) | 156 | 127 | ▼ 18.6% |
according to the US BTS · October 2024 → July 2026
On-time departures by month
On time = departure within 15 minutes of schedule. Non-cancelled flights with a recorded delay only.
The most recent periods19 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 88.9% | 100.0% | ▲ 12.5% |
| February | 78.6% | 100.0% | ▲ 27.3% |
| March | 100.0% | 69.0% | ▼ 31.0% |
| April | 73.1% | 42.9% | ▼ 41.4% |
| May | 70.6% | 0.0% | ▼ 100.0% |
| June | 57.1% | 29.0% | ▼ 49.3% |
| July | 46.7% | 21.4% | ▼ 54.1% |
| August | 92.0% | – | – |
| September | 80.0% | – | – |
| October | 100.0% | – | in progress |
| November | 100.0% | – | – |
| December | 25.0% | – | – |
| Year-to-date average (Jan–Jul) | 73.6% | 51.7% | ▼ 29.7% |
according to the US BTS · October 2024 → July 2026
Average departure delay by month
according to the US BTS · October 2024 → July 2026
Cancelled departures by month
The most recent periods19 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 0 | – |
| February | 0 | 0 | – |
| March | 0 | 2 | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 0 | 1 | – |
| July | 1 | 3 | ▲ 200.0% |
| August | 0 | – | – |
| September | 1 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 2 | – | – |
| Year to date (Jan–Jul) | 1 | 6 | ▲ 500.0% |
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 97.7% 419
- Cancelled 2.3% 10
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 31, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
6| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| MDW DEN Chicago Midway International Airport – Denver International Airport | 1,438 | 6.6 min | 83.5% | 85 |
| FLL BNA Fort Lauderdale Hollywood International Airport – Nashville International Airport | 1,278 | 16.0 min | 72.4% | 58 |
| RSW MDW Southwest Florida International Airport – Chicago Midway International Airport | 1,782 | 39.1 min | 36.7% | 50 |
| MDW LGA Chicago Midway International Airport – LaGuardia Airport | 1,164 | 54.0 min | 6.5% | 34 |
| PDX DEN Portland International Airport – Denver International Airport | 1,592 | 1.0 min | 100.0% | 31 |
| MCI PHX Kansas City International Airport – Phoenix Sky Harbor International Airport | 1,677 | 9.5 min | 83.3% | 31 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 26 | 26 | 92.3% | 0 |
| November 2024 | 19 | 19 | 79.0% | 0 |
| December 2024 | 10 | 10 | 90.0% | 0 |
| January 2025 | 27 | 27 | 88.9% | 0 |
| February 2025 | 28 | 28 | 78.6% | 0 |
| March 2025 | 4 | 4 | 100.0% | 0 |
| April 2025 | 26 | 26 | 73.1% | 0 |
| May 2025 | 34 | 34 | 70.6% | 0 |
| June 2025 | 21 | 21 | 57.1% | 0 |
| July 2025 | 16 | 15 | 46.7% | 1 |
| August 2025 | 25 | 25 | 92.0% | 0 |
| September 2025 | 26 | 25 | 80.0% | 1 |
| October 2025 | 31 | 31 | 100.0% | 0 |
| November 2025 | 3 | 3 | 100.0% | 0 |
| December 2025 | 6 | 4 | 25.0% | 2 |
| January 2026 | 1 | 1 | 100.0% | 0 |
| February 2026 | 3 | 3 | 100.0% | 0 |
| March 2026 | 31 | 29 | 69.0% | 2 |
| April 2026 | 7 | 7 | 42.9% | 0 |
| May 2026 | 1 | 1 | 0.0% | 0 |
| June 2026 | 39 | 38 | 29.0% | 1 |
| July 2026 | 45 | 42 | 21.4% | 3 |