WN3855
WN3855 (Southwest Airlines) is a multi-stop service on 23 routes, busiest St Louis to Boston. Of 378 departures recorded from October 2024 to July 2026, 75.1% left on time, according to the US BTS.
- On-time departures75.1%of 378 flights
- Average delay12.8 min
- July 202617
- Cancelled0.0%
- Legs flown under this number23
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 | 4 | 3 | ▼ 25.0% |
| February | – | – | – |
| March | 26 | 2 | ▼ 92.3% |
| April | 30 | 11 | ▼ 63.3% |
| May | 31 | 13 | ▼ 58.1% |
| June | 4 | 17 | ▲ 325.0% |
| July | – | 17 | – |
| August | 32 | – | – |
| September | 38 | – | – |
| October | 59 | – | in progress |
| November | 5 | – | – |
| December | 11 | – | – |
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 | 75.0% | 66.7% | ▼ 11.1% |
| February | – | – | – |
| March | 69.2% | 50.0% | ▼ 27.8% |
| April | 66.7% | 54.6% | ▼ 18.2% |
| May | 54.8% | 38.5% | ▼ 29.9% |
| June | 75.0% | 76.5% | ▲ 2.0% |
| July | – | 88.2% | – |
| August | 75.0% | – | – |
| September | 92.1% | – | – |
| October | 84.8% | – | in progress |
| November | 100.0% | – | – |
| December | 81.8% | – | – |
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 | – | – | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 0 | 0 | – |
| July | – | 0 | – |
| August | 0 | – | – |
| September | 0 | – | – |
| 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 100.0% 378
- Cancelled 0.0% 0
Share of all recorded flights in the period, all legs. · Oct 13, 2024 → Jul 29, 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 |
|---|---|---|---|---|
| STL BOS St. Louis Lambert International Airport – Boston Logan International Airport | 1,680 | 21.1 min | 63.8% | 58 |
| OAK LGB Oakland San Francisco Bay Airport – Long Beach International Airport | 569 | 5.0 min | 87.7% | 57 |
| DAL MAF Dallas Love Field – Midland International Air and Space Port | 513 | 21.3 min | 72.1% | 43 |
| TUS LAS Tucson International Airport – Harry Reid International Airport | 587 | -1.9 min | 100.0% | 31 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 17 | 17 | 88.2% | 0 |
| November 2024 | 36 | 36 | 75.0% | 0 |
| December 2024 | 22 | 22 | 72.7% | 0 |
| January 2025 | 4 | 4 | 75.0% | 0 |
| March 2025 | 26 | 26 | 69.2% | 0 |
| April 2025 | 30 | 30 | 66.7% | 0 |
| May 2025 | 31 | 31 | 54.8% | 0 |
| June 2025 | 4 | 4 | 75.0% | 0 |
| August 2025 | 32 | 32 | 75.0% | 0 |
| September 2025 | 38 | 38 | 92.1% | 0 |
| October 2025 | 59 | 59 | 84.8% | 0 |
| November 2025 | 5 | 5 | 100.0% | 0 |
| December 2025 | 11 | 11 | 81.8% | 0 |
| January 2026 | 3 | 3 | 66.7% | 0 |
| March 2026 | 2 | 2 | 50.0% | 0 |
| April 2026 | 11 | 11 | 54.6% | 0 |
| May 2026 | 13 | 13 | 38.5% | 0 |
| June 2026 | 17 | 17 | 76.5% | 0 |
| July 2026 | 17 | 17 | 88.2% | 0 |