WN4539
WN4539 (Southwest Airlines) is a multi-stop service on 20 routes, busiest San Diego to San Jose. Of 475 departures recorded from October 2024 to July 2026, 59.9% left on time, according to the US BTS.
- On-time departures59.9%of 475 flights
- Average delay21.2 min
- July 202658▲ 100.0%vs July 2025
- Cancelled1.3%
- Legs flown under this number20
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 | 6 | 15 | ▲ 150.0% |
| February | 10 | 19 | ▲ 90.0% |
| March | 1 | 25 | ▲ 2,400.0% |
| April | – | 5 | – |
| May | – | – | – |
| June | 28 | 51 | ▲ 82.1% |
| July | 29 | 58 | ▲ 100.0% |
| August | 39 | – | – |
| September | 39 | – | – |
| October | 52 | – | in progress |
| November | 31 | – | – |
| December | 31 | – | – |
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% | 50.0% | ▼ 25.0% |
| February | 70.0% | 31.6% | ▼ 54.9% |
| March | 100.0% | 36.0% | ▼ 64.0% |
| April | – | 20.0% | – |
| May | – | – | – |
| June | 60.7% | 27.5% | ▼ 54.8% |
| July | 57.1% | 51.7% | ▼ 9.5% |
| August | 62.2% | – | – |
| September | 71.1% | – | – |
| October | 92.3% | – | in progress |
| November | 77.4% | – | – |
| December | 53.3% | – | – |
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 | 1 | – |
| February | 0 | 0 | – |
| March | 0 | 0 | – |
| April | – | 0 | – |
| May | – | – | – |
| June | 0 | 0 | – |
| July | 1 | 0 | ▼ 100.0% |
| August | 2 | – | – |
| September | 1 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 1 | – | – |
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 98.7% 469
- Cancelled 1.3% 6
Share of all recorded flights in the period, all legs. · Oct 15, 2024 → Jul 31, 2026
On time, leg by leg
Departures within 15 minutes of schedule; small figure = departures recorded.
Legs flown under this number
6| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| SAN SJC San Diego International Airport – Mineta San Jose International Airport | 671 | 24.3 min | 62.1% | 59 |
| BOI OAK Boise Air Terminal/Gowen Field – Oakland San Francisco Bay Airport | 823 | 22.3 min | 54.4% | 57 |
| MDW CHS Chicago Midway International Airport – Charleston International Airport | 1,200 | 16.1 min | 70.8% | 49 |
| LAS TUS Harry Reid International Airport – Tucson International Airport | 587 | 9.6 min | 78.7% | 47 |
| SNA SMF John Wayne Orange County International Airport – Sacramento International Airport | 650 | -0.3 min | 96.8% | 31 |
| MCO IND Orlando International Airport – Indianapolis International Airport | 1,336 | 44.8 min | 37.9% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 6 | 6 | 100.0% | 0 |
| November 2024 | 12 | 12 | 75.0% | 0 |
| December 2024 | 18 | 18 | 88.9% | 0 |
| January 2025 | 6 | 6 | 66.7% | 0 |
| February 2025 | 10 | 10 | 70.0% | 0 |
| March 2025 | 1 | 1 | 100.0% | 0 |
| June 2025 | 28 | 28 | 60.7% | 0 |
| July 2025 | 29 | 28 | 57.1% | 1 |
| August 2025 | 39 | 37 | 62.2% | 2 |
| September 2025 | 39 | 38 | 71.1% | 1 |
| October 2025 | 52 | 52 | 92.3% | 0 |
| November 2025 | 31 | 31 | 77.4% | 0 |
| December 2025 | 31 | 30 | 53.3% | 1 |
| January 2026 | 15 | 14 | 50.0% | 1 |
| February 2026 | 19 | 19 | 31.6% | 0 |
| March 2026 | 25 | 25 | 36.0% | 0 |
| April 2026 | 5 | 5 | 20.0% | 0 |
| June 2026 | 51 | 51 | 27.5% | 0 |
| July 2026 | 58 | 58 | 51.7% | 0 |