WN4253
WN4253 (Southwest Airlines) is a multi-stop service on 23 routes, busiest San Jose to Ontario. Of 361 departures recorded from October 2024 to July 2026, 72.1% left on time, according to the US BTS.
- On-time departures72.1%of 361 flights
- Average delay17.6 min
- July 202625▲ 19.0%vs July 2025
- Cancelled0.8%
- 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 | 12 | 5 | ▼ 58.3% |
| February | 27 | – | – |
| March | 8 | 28 | ▲ 250.0% |
| April | 1 | 34 | ▲ 3,300.0% |
| May | – | 36 | – |
| June | 20 | 14 | ▼ 30.0% |
| July | 21 | 25 | ▲ 19.0% |
| August | 8 | – | – |
| September | 4 | – | – |
| October | – | – | in progress |
| November | 27 | – | – |
| December | 27 | – | – |
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% | 20.0% | ▼ 73.3% |
| February | 100.0% | – | – |
| March | 75.0% | 78.6% | ▲ 4.8% |
| April | 0.0% | 94.1% | – |
| May | – | 88.9% | – |
| June | 50.0% | 64.3% | ▲ 28.6% |
| July | 50.0% | 52.0% | ▲ 4.0% |
| August | 37.5% | – | – |
| September | 100.0% | – | – |
| October | – | – | in progress |
| November | 46.2% | – | – |
| December | 37.0% | – | – |
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 | 1 | – | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | – | 0 | – |
| June | 0 | 0 | – |
| July | 1 | 0 | ▼ 100.0% |
| August | 0 | – | – |
| September | 0 | – | – |
| October | – | – | in progress |
| November | 1 | – | – |
| 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 99.2% 358
- Cancelled 0.8% 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
5| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| SJC ONT Mineta San Jose International Airport – Ontario International Airport | 536 | -1.9 min | 93.1% | 58 |
| SAN SFO San Diego International Airport – San Francisco International Airport | 719 | 40.3 min | 37.5% | 57 |
| MSY SAT Louis Armstrong New Orleans International Airport – San Antonio International Airport | 794 | -0.3 min | 93.5% | 46 |
| BWI ATL Baltimore/Washington International Thurgood Marshall Airport – Hartsfield Jackson Atlanta International Airport | 928 | 61.5 min | 40.0% | 36 |
| PHX SAT Phoenix Sky Harbor International Airport – San Antonio International Airport | 1,354 | 4.1 min | 86.7% | 30 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 28 | 28 | 96.4% | 0 |
| November 2024 | 14 | 14 | 85.7% | 0 |
| December 2024 | 22 | 22 | 90.9% | 0 |
| January 2025 | 12 | 12 | 75.0% | 0 |
| February 2025 | 27 | 26 | 100.0% | 1 |
| March 2025 | 8 | 8 | 75.0% | 0 |
| April 2025 | 1 | 1 | 0.0% | 0 |
| June 2025 | 20 | 20 | 50.0% | 0 |
| July 2025 | 21 | 20 | 50.0% | 1 |
| August 2025 | 8 | 8 | 37.5% | 0 |
| September 2025 | 4 | 4 | 100.0% | 0 |
| November 2025 | 27 | 26 | 46.2% | 1 |
| December 2025 | 27 | 27 | 37.0% | 0 |
| January 2026 | 5 | 5 | 20.0% | 0 |
| March 2026 | 28 | 28 | 78.6% | 0 |
| April 2026 | 34 | 34 | 94.1% | 0 |
| May 2026 | 36 | 36 | 88.9% | 0 |
| June 2026 | 14 | 14 | 64.3% | 0 |
| July 2026 | 25 | 25 | 52.0% | 0 |