WN399
WN399 (Southwest Airlines) is a multi-stop service on 38 routes, busiest St Louis to Baltimore. Of 711 departures recorded from October 2024 to July 2026, 76.7% left on time, according to the US BTS.
- On-time departures76.7%of 711 flights
- Average delay14.8 min
- July 202645▲ 95.7%vs July 2025
- Cancelled1.7%
- Legs flown under this number38
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 | 31 | 35 | ▲ 12.9% |
| February | 28 | 46 | ▲ 64.3% |
| March | 27 | 33 | ▲ 22.2% |
| April | 29 | 30 | ▲ 3.4% |
| May | 30 | 31 | ▲ 3.3% |
| June | 22 | 42 | ▲ 90.9% |
| July | 23 | 45 | ▲ 95.7% |
| August | 31 | – | – |
| September | 30 | – | – |
| October | 31 | – | in progress |
| November | 30 | – | – |
| December | 31 | – | – |
| Year to date (Jan–Jul) | 190 | 262 | ▲ 37.9% |
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% | 91.2% | ▲ 2.6% |
| February | 96.3% | 97.8% | ▲ 1.5% |
| March | 85.2% | 75.8% | ▼ 11.1% |
| April | 82.8% | 80.0% | ▼ 3.3% |
| May | 56.7% | 79.3% | ▲ 40.0% |
| June | 72.7% | 69.1% | ▼ 5.1% |
| July | 69.6% | 37.2% | ▼ 46.5% |
| August | 77.4% | – | – |
| September | 83.3% | – | – |
| October | 93.6% | – | in progress |
| November | 53.3% | – | – |
| December | 53.3% | – | – |
| Year-to-date average (Jan–Jul) | 78.9% | 75.8% | ▼ 4.0% |
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 | 4 | 1 | ▼ 75.0% |
| February | 1 | 1 | 0.0% |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 0 | 2 | – |
| June | 0 | 0 | – |
| July | 0 | 2 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 1 | – | – |
| Year to date (Jan–Jul) | 5 | 6 | ▲ 20.0% |
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 98.3% 699
- Cancelled 1.7% 12
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
10Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 23 | 23 | 69.6% | 0 |
| November 2024 | 39 | 39 | 92.3% | 0 |
| December 2024 | 44 | 44 | 81.8% | 0 |
| January 2025 | 31 | 27 | 88.9% | 4 |
| February 2025 | 28 | 27 | 96.3% | 1 |
| March 2025 | 27 | 27 | 85.2% | 0 |
| April 2025 | 29 | 29 | 82.8% | 0 |
| May 2025 | 30 | 30 | 56.7% | 0 |
| June 2025 | 22 | 22 | 72.7% | 0 |
| July 2025 | 23 | 23 | 69.6% | 0 |
| August 2025 | 31 | 31 | 77.4% | 0 |
| September 2025 | 30 | 30 | 83.3% | 0 |
| October 2025 | 31 | 31 | 93.6% | 0 |
| November 2025 | 30 | 30 | 53.3% | 0 |
| December 2025 | 31 | 30 | 53.3% | 1 |
| January 2026 | 35 | 34 | 91.2% | 1 |
| February 2026 | 46 | 45 | 97.8% | 1 |
| March 2026 | 33 | 33 | 75.8% | 0 |
| April 2026 | 30 | 30 | 80.0% | 0 |
| May 2026 | 31 | 29 | 79.3% | 2 |
| June 2026 | 42 | 42 | 69.1% | 0 |
| July 2026 | 45 | 43 | 37.2% | 2 |