WN4520
WN4520 (Southwest Airlines) is a multi-stop service on 21 routes, busiest Burbank to Denver. Of 338 departures recorded from October 2024 to July 2026, 77.9% left on time, according to the US BTS.
- On-time departures77.9%of 338 flights
- Average delay11.2 min
- July 202614▼ 67.4%vs July 2025
- Cancelled0.9%
- Legs flown under this number21
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 | 3 | 2 | ▼ 33.3% |
| February | – | 2 | – |
| March | 22 | – | – |
| April | 37 | 8 | ▼ 78.4% |
| May | 39 | 9 | ▼ 76.9% |
| June | 44 | 14 | ▼ 68.2% |
| July | 43 | 14 | ▼ 67.4% |
| August | 10 | – | – |
| September | 4 | – | – |
| October | – | – | in progress |
| November | 26 | – | – |
| December | 20 | – | – |
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 | 66.7% | 100.0% | ▲ 50.0% |
| February | – | 100.0% | – |
| March | 77.3% | – | – |
| April | 89.2% | 75.0% | ▼ 15.9% |
| May | 92.3% | 88.9% | ▼ 3.7% |
| June | 90.7% | 35.7% | ▼ 60.6% |
| July | 79.1% | 16.7% | ▼ 78.9% |
| August | 70.0% | – | – |
| September | 50.0% | – | – |
| October | – | – | in progress |
| November | 69.2% | – | – |
| December | 85.0% | – | – |
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 | – | – |
| April | 0 | 0 | – |
| May | 0 | 0 | – |
| June | 1 | 0 | ▼ 100.0% |
| July | 0 | 2 | – |
| 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 99.1% 335
- Cancelled 0.9% 3
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
4| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| BUR DEN Hollywood Burbank/Bob Hope Airport – Denver International Airport | 1,366 | 18.9 min | 78.3% | 46 |
| SJC SNA Mineta San Jose International Airport – John Wayne Orange County International Airport | 550 | 0.4 min | 90.5% | 43 |
| BNA ORD Nashville International Airport – Chicago O'Hare International Airport | 660 | 2.2 min | 92.5% | 40 |
| BNA BWI Nashville International Airport – Baltimore/Washington International Thurgood Marshall Airport | 944 | 14.4 min | 76.7% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 13 | 13 | 69.2% | 0 |
| November 2024 | 16 | 16 | 87.5% | 0 |
| December 2024 | 12 | 12 | 66.7% | 0 |
| January 2025 | 3 | 3 | 66.7% | 0 |
| March 2025 | 22 | 22 | 77.3% | 0 |
| April 2025 | 37 | 37 | 89.2% | 0 |
| May 2025 | 39 | 39 | 92.3% | 0 |
| June 2025 | 44 | 43 | 90.7% | 1 |
| July 2025 | 43 | 43 | 79.1% | 0 |
| August 2025 | 10 | 10 | 70.0% | 0 |
| September 2025 | 4 | 4 | 50.0% | 0 |
| November 2025 | 26 | 26 | 69.2% | 0 |
| December 2025 | 20 | 20 | 85.0% | 0 |
| January 2026 | 2 | 2 | 100.0% | 0 |
| February 2026 | 2 | 2 | 100.0% | 0 |
| April 2026 | 8 | 8 | 75.0% | 0 |
| May 2026 | 9 | 9 | 88.9% | 0 |
| June 2026 | 14 | 14 | 35.7% | 0 |
| July 2026 | 14 | 12 | 16.7% | 2 |