WN4521
WN4521 (Southwest Airlines) is a multi-stop service on 17 routes, busiest Las Vegas to Nashville. Of 329 departures recorded from October 2024 to July 2026, 68.7% left on time, according to the US BTS.
- On-time departures68.7%of 329 flights
- Average delay18.3 min
- July 202630▲ 650.0%vs July 2025
- Cancelled0.0%
- Legs flown under this number17
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 | 2 | 4 | ▲ 100.0% |
| February | 10 | 8 | ▼ 20.0% |
| March | 2 | 5 | ▲ 150.0% |
| April | 23 | 25 | ▲ 8.7% |
| May | 31 | 31 | 0.0% |
| June | 8 | 30 | ▲ 275.0% |
| July | 4 | 30 | ▲ 650.0% |
| August | 15 | – | – |
| September | 17 | – | – |
| October | 13 | – | in progress |
| November | 16 | – | – |
| December | 15 | – | – |
| Year to date (Jan–Jul) | 80 | 133 | ▲ 66.3% |
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 | 100.0% | 75.0% | ▼ 25.0% |
| February | 40.0% | 87.5% | ▲ 118.8% |
| March | 100.0% | 20.0% | ▼ 80.0% |
| April | 78.3% | 84.0% | ▲ 7.3% |
| May | 90.3% | 83.9% | ▼ 7.1% |
| June | 75.0% | 50.0% | ▼ 33.3% |
| July | 75.0% | 30.0% | ▼ 60.0% |
| August | 53.3% | – | – |
| September | 58.8% | – | – |
| October | 92.3% | – | in progress |
| November | 75.0% | – | – |
| December | 60.0% | – | – |
| Year-to-date average (Jan–Jul) | 79.8% | 61.5% | ▼ 23.0% |
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 | 0 | 0 | – |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 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) | 0 | 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% 329
- Cancelled 0.0% 0
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
5| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| STL TPA St. Louis Lambert International Airport – Tampa International Airport | 1,400 | 14.1 min | 86.2% | 58 |
| LAS BNA Harry Reid International Airport – Nashville International Airport | 2,549 | 3.1 min | 82.8% | 58 |
| ABQ SAN Albuquerque International Sunport – San Diego International Airport | 1,009 | 44.8 min | 36.8% | 57 |
| HOU LAS William P. Hobby Airport – Harry Reid International Airport | 1,985 | 28.0 min | 62.2% | 37 |
| OAK LAX Oakland San Francisco Bay Airport – Los Angeles International Airport | 543 | 20.4 min | 54.8% | 31 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 15 | 15 | 86.7% | 0 |
| November 2024 | 11 | 11 | 72.7% | 0 |
| December 2024 | 14 | 14 | 64.3% | 0 |
| January 2025 | 2 | 2 | 100.0% | 0 |
| February 2025 | 10 | 10 | 40.0% | 0 |
| March 2025 | 2 | 2 | 100.0% | 0 |
| April 2025 | 23 | 23 | 78.3% | 0 |
| May 2025 | 31 | 31 | 90.3% | 0 |
| June 2025 | 8 | 8 | 75.0% | 0 |
| July 2025 | 4 | 4 | 75.0% | 0 |
| August 2025 | 15 | 15 | 53.3% | 0 |
| September 2025 | 17 | 17 | 58.8% | 0 |
| October 2025 | 13 | 13 | 92.3% | 0 |
| November 2025 | 16 | 16 | 75.0% | 0 |
| December 2025 | 15 | 15 | 60.0% | 0 |
| January 2026 | 4 | 4 | 75.0% | 0 |
| February 2026 | 8 | 8 | 87.5% | 0 |
| March 2026 | 5 | 5 | 20.0% | 0 |
| April 2026 | 25 | 25 | 84.0% | 0 |
| May 2026 | 31 | 31 | 83.9% | 0 |
| June 2026 | 30 | 30 | 50.0% | 0 |
| July 2026 | 30 | 30 | 30.0% | 0 |