WN4577
WN4577 (Southwest Airlines) is a multi-stop service on 25 routes, busiest Baltimore to Buffalo. Of 248 departures recorded from October 2024 to July 2026, 71.3% left on time, according to the US BTS.
- On-time departures71.3%of 248 flights
- Average delay15.1 min
- July 202621▲ 0.0%vs July 2025
- Cancelled1.6%
- Legs flown under this number25
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 | 2 | 2 | 0.0% |
| February | – | 4 | – |
| March | 40 | 32 | ▼ 20.0% |
| April | 10 | 7 | ▼ 30.0% |
| May | – | 1 | – |
| June | 20 | 20 | 0.0% |
| July | 21 | 21 | 0.0% |
| August | 8 | – | – |
| September | 4 | – | – |
| October | – | – | in progress |
| November | 11 | – | – |
| December | 15 | – | – |
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% | 100.0% | – |
| February | – | 75.0% | – |
| March | 82.5% | 50.0% | ▼ 39.4% |
| April | 40.0% | 66.7% | ▲ 66.7% |
| May | – | 100.0% | – |
| June | 80.0% | 52.6% | ▼ 34.2% |
| July | 75.0% | 65.0% | ▼ 13.3% |
| August | 62.5% | – | – |
| September | 75.0% | – | – |
| October | – | – | in progress |
| November | 100.0% | – | – |
| December | 80.0% | – | – |
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 periods16 periods
| Period | Cancelled 2025 | Cancelled 2026 | Change vs last year |
|---|---|---|---|
| January | 0 | 0 | – |
| February | – | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 1 | – |
| May | – | 0 | – |
| June | 0 | 1 | – |
| July | 1 | 1 | 0.0% |
| August | 0 | – | – |
| September | 0 | – | – |
| October | – | – | 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 98.4% 244
- Cancelled 1.6% 4
Share of all recorded flights in the period, all legs. · Oct 12, 2024 → Jul 31, 2026
Legs flown under this number
1| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| BWI BUF Baltimore/Washington International Thurgood Marshall Airport – Buffalo Niagara International Airport | 453 | 33.1 min | 54.8% | 33 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 19 | 19 | 79.0% | 0 |
| November 2024 | 7 | 7 | 100.0% | 0 |
| December 2024 | 4 | 4 | 100.0% | 0 |
| January 2025 | 2 | 2 | 0.0% | 0 |
| March 2025 | 40 | 40 | 82.5% | 0 |
| April 2025 | 10 | 10 | 40.0% | 0 |
| June 2025 | 20 | 20 | 80.0% | 0 |
| July 2025 | 21 | 20 | 75.0% | 1 |
| August 2025 | 8 | 8 | 62.5% | 0 |
| September 2025 | 4 | 4 | 75.0% | 0 |
| November 2025 | 11 | 11 | 100.0% | 0 |
| December 2025 | 15 | 15 | 80.0% | 0 |
| January 2026 | 2 | 2 | 100.0% | 0 |
| February 2026 | 4 | 4 | 75.0% | 0 |
| March 2026 | 32 | 32 | 50.0% | 0 |
| April 2026 | 7 | 6 | 66.7% | 1 |
| May 2026 | 1 | 1 | 100.0% | 0 |
| June 2026 | 20 | 19 | 52.6% | 1 |
| July 2026 | 21 | 20 | 65.0% | 1 |