WN4135
WN4135 (Southwest Airlines) is a multi-stop service on 21 routes, busiest Tucson to San Diego. Of 318 departures recorded from October 2024 to July 2026, 74.5% left on time, according to the US BTS.
- On-time departures74.5%of 318 flights
- Average delay11.8 min
- July 202623
- Cancelled0.3%
- 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 | 2 | 27 | ▲ 1,250.0% |
| February | 2 | 28 | ▲ 1,300.0% |
| March | 31 | 31 | 0.0% |
| April | 25 | 27 | ▲ 8.0% |
| May | 22 | 28 | ▲ 27.3% |
| June | 3 | 14 | ▲ 366.7% |
| July | – | 23 | – |
| August | – | – | – |
| September | – | – | – |
| October | 25 | – | in progress |
| November | 1 | – | – |
| December | 2 | – | – |
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 | 50.0% | 100.0% | ▲ 100.0% |
| February | 50.0% | 96.4% | ▲ 92.9% |
| March | 96.8% | 100.0% | ▲ 3.3% |
| April | 80.0% | 55.6% | ▼ 30.6% |
| May | 57.1% | 35.7% | ▼ 37.5% |
| June | 100.0% | 35.7% | ▼ 64.3% |
| July | – | 69.6% | – |
| August | – | – | – |
| September | – | – | – |
| October | 64.0% | – | in progress |
| November | 0.0% | – | – |
| December | 50.0% | – | – |
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 | 0 | – |
| March | 0 | 0 | – |
| April | 0 | 0 | – |
| May | 1 | 0 | ▼ 100.0% |
| June | 0 | 0 | – |
| July | – | 0 | – |
| August | – | – | – |
| September | – | – | – |
| 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 99.7% 317
- Cancelled 0.3% 1
Share of all recorded flights in the period, all legs. · Oct 15, 2024 → Jul 29, 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 |
|---|---|---|---|---|
| TUS SAN Tucson International Airport – San Diego International Airport | 591 | -4.4 min | 98.3% | 58 |
| SAN SMF San Diego International Airport – Sacramento International Airport | 773 | 29.9 min | 36.7% | 49 |
| BWI DAL Baltimore/Washington International Thurgood Marshall Airport – Dallas Love Field | 1,942 | 11.4 min | 70.7% | 42 |
| PHL MDW Philadelphia International Airport – Chicago Midway International Airport | 1,073 | 0.3 min | 93.9% | 33 |
| ONT OAK Ontario International Airport – Oakland San Francisco Bay Airport | 582 | -5.6 min | 100.0% | 33 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 6 | 6 | 100.0% | 0 |
| November 2024 | 15 | 15 | 73.3% | 0 |
| December 2024 | 6 | 6 | 66.7% | 0 |
| January 2025 | 2 | 2 | 50.0% | 0 |
| February 2025 | 2 | 2 | 50.0% | 0 |
| March 2025 | 31 | 31 | 96.8% | 0 |
| April 2025 | 25 | 25 | 80.0% | 0 |
| May 2025 | 22 | 21 | 57.1% | 1 |
| June 2025 | 3 | 3 | 100.0% | 0 |
| October 2025 | 25 | 25 | 64.0% | 0 |
| November 2025 | 1 | 1 | 0.0% | 0 |
| December 2025 | 2 | 2 | 50.0% | 0 |
| January 2026 | 27 | 27 | 100.0% | 0 |
| February 2026 | 28 | 28 | 96.4% | 0 |
| March 2026 | 31 | 31 | 100.0% | 0 |
| April 2026 | 27 | 27 | 55.6% | 0 |
| May 2026 | 28 | 28 | 35.7% | 0 |
| June 2026 | 14 | 14 | 35.7% | 0 |
| July 2026 | 23 | 23 | 69.6% | 0 |