WN551
WN551 (Southwest Airlines) is a multi-stop service on 48 routes, busiest Boston to Baltimore. Of 798 departures recorded from October 2024 to July 2026, 64.7% left on time, according to the US BTS.
- On-time departures64.7%of 798 flights
- Average delay20.3 min
- July 202634▼ 19.0%vs July 2025
- Cancelled0.5%
- Legs flown under this number48
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 | 40 | 31 | ▼ 22.5% |
| February | 35 | 28 | ▼ 20.0% |
| March | 44 | 31 | ▼ 29.5% |
| April | 33 | 56 | ▲ 69.7% |
| May | 31 | 67 | ▲ 116.1% |
| June | 36 | 36 | 0.0% |
| July | 42 | 34 | ▼ 19.0% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 29 | – | – |
| December | 31 | – | – |
| Year to date (Jan–Jul) | 261 | 283 | ▲ 8.4% |
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 | 85.0% | 93.6% | ▲ 10.1% |
| February | 77.1% | 96.4% | ▲ 25.0% |
| March | 95.4% | 40.0% | ▼ 58.0% |
| April | 51.6% | 39.3% | ▼ 23.9% |
| May | 41.9% | 49.3% | ▲ 17.4% |
| June | 50.0% | 47.2% | ▼ 5.6% |
| July | 50.0% | 23.5% | ▼ 52.9% |
| August | 77.4% | – | – |
| September | 93.3% | – | – |
| October | 64.5% | – | in progress |
| November | 69.0% | – | – |
| December | 67.7% | – | – |
| Year-to-date average (Jan–Jul) | 64.4% | 55.6% | ▼ 13.7% |
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 | 1 | 1 | 0.0% |
| April | 2 | 0 | ▼ 100.0% |
| May | 0 | 0 | – |
| June | 0 | 0 | – |
| July | 0 | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 3 | 1 | ▼ 66.7% |
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 99.5% 794
- Cancelled 0.5% 4
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
12Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 20 | 20 | 85.0% | 0 |
| November 2024 | 33 | 33 | 87.9% | 0 |
| December 2024 | 49 | 49 | 75.5% | 0 |
| January 2025 | 40 | 40 | 85.0% | 0 |
| February 2025 | 35 | 35 | 77.1% | 0 |
| March 2025 | 44 | 43 | 95.4% | 1 |
| April 2025 | 33 | 31 | 51.6% | 2 |
| May 2025 | 31 | 31 | 41.9% | 0 |
| June 2025 | 36 | 36 | 50.0% | 0 |
| July 2025 | 42 | 42 | 50.0% | 0 |
| August 2025 | 31 | 31 | 77.4% | 0 |
| September 2025 | 30 | 30 | 93.3% | 0 |
| October 2025 | 31 | 31 | 64.5% | 0 |
| November 2025 | 29 | 29 | 69.0% | 0 |
| December 2025 | 31 | 31 | 67.7% | 0 |
| January 2026 | 31 | 31 | 93.6% | 0 |
| February 2026 | 28 | 28 | 96.4% | 0 |
| March 2026 | 31 | 30 | 40.0% | 1 |
| April 2026 | 56 | 56 | 39.3% | 0 |
| May 2026 | 67 | 67 | 49.3% | 0 |
| June 2026 | 36 | 36 | 47.2% | 0 |
| July 2026 | 34 | 34 | 23.5% | 0 |