WN1435
WN1435 (Southwest Airlines) is a multi-stop service on 43 routes, busiest Boston to Chicago. Of 758 departures recorded from October 2024 to July 2026, 77.5% left on time, according to the US BTS.
- On-time departures77.5%of 758 flights
- Average delay11.9 min
- July 202654▲ 25.6%vs July 2025
- Cancelled1.6%
- Legs flown under this number43
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 | 36 | 21 | ▼ 41.7% |
| February | 28 | 16 | ▼ 42.9% |
| March | 32 | 22 | ▼ 31.3% |
| April | 35 | 16 | ▼ 54.3% |
| May | 35 | 13 | ▼ 62.9% |
| June | 43 | 50 | ▲ 16.3% |
| July | 43 | 54 | ▲ 25.6% |
| August | 25 | – | – |
| September | 21 | – | – |
| October | 30 | – | in progress |
| November | 38 | – | – |
| December | 59 | – | – |
| Year to date (Jan–Jul) | 252 | 192 | ▼ 23.8% |
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 | 82.4% | 89.5% | ▲ 8.6% |
| February | 77.8% | 68.8% | ▼ 11.6% |
| March | 84.4% | 85.7% | ▲ 1.6% |
| April | 82.4% | 75.0% | ▼ 8.9% |
| May | 69.7% | 61.5% | ▼ 11.7% |
| June | 62.8% | 65.3% | ▲ 4.0% |
| July | 81.0% | 52.8% | ▼ 34.7% |
| August | 84.0% | – | – |
| September | 71.4% | – | – |
| October | 96.7% | – | in progress |
| November | 73.7% | – | – |
| December | 81.4% | – | – |
| Year-to-date average (Jan–Jul) | 77.2% | 71.2% | ▼ 7.7% |
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 | 2 | 2 | 0.0% |
| February | 1 | 0 | ▼ 100.0% |
| March | 0 | 1 | – |
| April | 1 | 0 | ▼ 100.0% |
| May | 2 | 0 | ▼ 100.0% |
| June | 0 | 1 | – |
| July | 1 | 1 | 0.0% |
| August | 0 | – | – |
| September | 0 | – | – |
| October | 0 | – | in progress |
| November | 0 | – | – |
| December | 0 | – | – |
| Year to date (Jan–Jul) | 7 | 5 | ▼ 28.6% |
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 98.4% 746
- Cancelled 1.6% 12
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
7| Routes | Distance (km) | Avg delay | On time | Departures |
|---|---|---|---|---|
| BOS MDW Boston Logan International Airport – Chicago Midway International Airport | 1,381 | 9.0 min | 84.0% | 100 |
| MSY LAS Louis Armstrong New Orleans International Airport – Harry Reid International Airport | 2,409 | 11.6 min | 75.7% | 70 |
| TPA BWI Tampa International Airport – Baltimore/Washington International Thurgood Marshall Airport | 1,358 | 19.3 min | 79.6% | 51 |
| ONT LAS Ontario International Airport – Harry Reid International Airport | 317 | 21.6 min | 68.3% | 42 |
| LAS RNO Harry Reid International Airport – Reno Tahoe International Airport | 556 | 13.1 min | 79.4% | 36 |
| BDL MDW Bradley International Airport – Chicago Midway International Airport | 1,246 | 0.7 min | 97.0% | 33 |
| BOI DEN Boise Air Terminal/Gowen Field – Denver International Airport | 1,042 | -0.4 min | 96.8% | 31 |
Monthly figures
| Period | Departures | With departure delay recorded | On time | Cancelled |
|---|---|---|---|---|
| October 2024 | 30 | 30 | 63.3% | 0 |
| November 2024 | 44 | 44 | 90.9% | 0 |
| December 2024 | 67 | 67 | 95.5% | 0 |
| January 2025 | 36 | 34 | 82.4% | 2 |
| February 2025 | 28 | 27 | 77.8% | 1 |
| March 2025 | 32 | 32 | 84.4% | 0 |
| April 2025 | 35 | 34 | 82.4% | 1 |
| May 2025 | 35 | 33 | 69.7% | 2 |
| June 2025 | 43 | 43 | 62.8% | 0 |
| July 2025 | 43 | 42 | 81.0% | 1 |
| August 2025 | 25 | 25 | 84.0% | 0 |
| September 2025 | 21 | 21 | 71.4% | 0 |
| October 2025 | 30 | 30 | 96.7% | 0 |
| November 2025 | 38 | 38 | 73.7% | 0 |
| December 2025 | 59 | 59 | 81.4% | 0 |
| January 2026 | 21 | 19 | 89.5% | 2 |
| February 2026 | 16 | 16 | 68.8% | 0 |
| March 2026 | 22 | 21 | 85.7% | 1 |
| April 2026 | 16 | 16 | 75.0% | 0 |
| May 2026 | 13 | 13 | 61.5% | 0 |
| June 2026 | 50 | 49 | 65.3% | 1 |
| July 2026 | 54 | 53 | 52.8% | 1 |