WN4187
WN4187 (Southwest Airlines) is a multi-stop service on 19 routes, busiest Philadelphia to Denver. Of 339 departures recorded from October 2024 to July 2026, 71.8% left on time, according to the US BTS.
- On-time departures71.8%of 339 flights
- Average delay15.1 min
- July 202622▼ 26.7%vs July 2025
- Cancelled1.8%
- Legs flown under this number19
Recorded departures by month
All legs under this number combined; see the leg table.
Months without data are left blank.
The most recent periods18 periods
| Period | Departures 2025 | Departures 2026 | Change vs last year |
|---|---|---|---|
| January | 1 | 31 | ▲ 3,000.0% |
| February | 2 | 28 | ▲ 1,300.0% |
| March | 25 | 8 | ▼ 68.0% |
| April | 6 | 4 | ▼ 33.3% |
| May | – | 5 | – |
| June | 26 | 20 | ▼ 23.1% |
| July | 30 | 22 | ▼ 26.7% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 3 | – | in progress |
| November | 8 | – | – |
| December | 20 | – | – |
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 periods18 periods
| Period | On time 2025 | On time 2026 | Change vs last year |
|---|---|---|---|
| January | 100.0% | 67.7% | ▼ 32.3% |
| February | 50.0% | 57.1% | ▲ 14.3% |
| March | 68.2% | 50.0% | ▼ 26.7% |
| April | 83.3% | 0.0% | ▼ 100.0% |
| May | – | 20.0% | – |
| June | 88.5% | 75.0% | ▼ 15.2% |
| July | 80.0% | 90.9% | ▲ 13.6% |
| August | 87.1% | – | – |
| September | 90.0% | – | – |
| October | 100.0% | – | in progress |
| November | 62.5% | – | – |
| December | 5.6% | – | – |
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 periods18 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 0 | – |
| February | 0 | 0 | – |
| March | 3 | 0 | ▼ 100.0% |
| April | 0 | 0 | – |
| May | – | 0 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 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 98.2% 333
- Cancelled 1.8% 6
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
4| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| PHL DEN Philadelphia International Airport – Denver International Airport | 2,501 | 9.0 min | 85.0% | 60 |
| SAN HNL San Diego International Airport – Daniel K. Inouye International Airport | 4,201 | 4.5 min | 87.9% | 58 |
| DEN MCO Denver International Airport – Orlando International Airport | 2,486 | 17.9 min | 60.0% | 55 |
| SAN SMF San Diego International Airport – Sacramento International Airport | 773 | 10.6 min | 79.4% | 34 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 75.0% | 0 |
| November 2024 | 15 | 14 | 78.6% | 1 |
| December 2024 | 4 | 4 | 100.0% | 0 |
| January 2025 | 1 | 1 | 100.0% | 0 |
| February 2025 | 2 | 2 | 50.0% | 0 |
| March 2025 | 25 | 22 | 68.2% | 3 |
| April 2025 | 6 | 6 | 83.3% | 0 |
| June 2025 | 26 | 26 | 88.5% | 0 |
| July 2025 | 30 | 30 | 80.0% | 0 |
| August 2025 | 31 | 31 | 87.1% | 0 |
| September 2025 | 30 | 30 | 90.0% | 0 |
| October 2025 | 3 | 3 | 100.0% | 0 |
| November 2025 | 8 | 8 | 62.5% | 0 |
| December 2025 | 20 | 18 | 5.6% | 2 |
| January 2026 | 31 | 31 | 67.7% | 0 |
| February 2026 | 28 | 28 | 57.1% | 0 |
| March 2026 | 8 | 8 | 50.0% | 0 |
| April 2026 | 4 | 4 | 0.0% | 0 |
| May 2026 | 5 | 5 | 20.0% | 0 |
| June 2026 | 20 | 20 | 75.0% | 0 |
| July 2026 | 22 | 22 | 90.9% | 0 |