WN3877
WN3877 (Southwest Airlines) is a multi-stop service on 28 routes, busiest Chicago to Philadelphia. Of 522 departures recorded from October 2024 to July 2026, 66.5% left on time, according to the US BTS.
- On-time departures66.5%of 522 flights
- Average delay22.0 min
- July 202645▲ 18.4%vs July 2025
- Cancelled0.6%
- Legs flown under this number28
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 | 2 | 1 | ▼ 50.0% |
| February | – | – | – |
| March | 26 | 9 | ▼ 65.4% |
| April | 30 | 36 | ▲ 20.0% |
| May | 31 | 44 | ▲ 41.9% |
| June | 38 | 41 | ▲ 7.9% |
| July | 38 | 45 | ▲ 18.4% |
| August | 51 | – | – |
| September | 52 | – | – |
| October | 32 | – | in progress |
| November | 5 | – | – |
| December | 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 | 100.0% | 0.0% | ▼ 100.0% |
| February | – | – | – |
| March | 65.4% | 88.9% | ▲ 36.0% |
| April | 70.0% | 38.9% | ▼ 44.4% |
| May | 74.2% | 15.9% | ▼ 78.6% |
| June | 86.8% | 80.5% | ▼ 7.3% |
| July | 79.0% | 68.9% | ▼ 12.7% |
| August | 64.7% | – | – |
| September | 71.4% | – | – |
| October | 87.5% | – | in progress |
| November | 60.0% | – | – |
| December | 0.0% | – | – |
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 | 0 | – |
| February | – | – | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 3 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| 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 99.4% 519
- Cancelled 0.6% 3
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
6| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| MDW PHL Chicago Midway International Airport – Philadelphia International Airport | 1,073 | 17.2 min | 80.0% | 60 |
| PHX SAT Phoenix Sky Harbor International Airport – San Antonio International Airport | 1,354 | 40.0 min | 32.8% | 58 |
| PDX PHX Portland International Airport – Phoenix Sky Harbor International Airport | 1,625 | 17.3 min | 72.4% | 58 |
| MDW IND Chicago Midway International Airport – Indianapolis International Airport | 261 | 6.8 min | 82.0% | 50 |
| PHX DEN Phoenix Sky Harbor International Airport – Denver International Airport | 968 | 37.3 min | 53.7% | 42 |
| OAK SAN Oakland San Francisco Bay Airport – San Diego International Airport | 718 | 11.8 min | 84.4% | 32 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 26 | 26 | 53.9% | 0 |
| November 2024 | 5 | 5 | 100.0% | 0 |
| December 2024 | 8 | 8 | 100.0% | 0 |
| January 2025 | 2 | 2 | 100.0% | 0 |
| March 2025 | 26 | 26 | 65.4% | 0 |
| April 2025 | 30 | 30 | 70.0% | 0 |
| May 2025 | 31 | 31 | 74.2% | 0 |
| June 2025 | 38 | 38 | 86.8% | 0 |
| July 2025 | 38 | 38 | 79.0% | 0 |
| August 2025 | 51 | 51 | 64.7% | 0 |
| September 2025 | 52 | 49 | 71.4% | 3 |
| October 2025 | 32 | 32 | 87.5% | 0 |
| November 2025 | 5 | 5 | 60.0% | 0 |
| December 2025 | 2 | 2 | 0.0% | 0 |
| January 2026 | 1 | 1 | 0.0% | 0 |
| March 2026 | 9 | 9 | 88.9% | 0 |
| April 2026 | 36 | 36 | 38.9% | 0 |
| May 2026 | 44 | 44 | 15.9% | 0 |
| June 2026 | 41 | 41 | 80.5% | 0 |
| July 2026 | 45 | 45 | 68.9% | 0 |