Flight profile · Southwest Airlines
WN1636
Houston (HOU) to Dallas (DAL) · scheduled 6:00 AM – 7:05 AM
How WN1636 performs
886 operations, July 2023 – July 2026.
WN1636 arrived on time 94.4% of the time, against 81.3% for all HOU → DAL flights, so this departure is 13.1 percentage points better than the route as a whole. Against Southwest Airlines’ own flights on this route it is 13.1 points better.
Source: US DOT Bureau of Transportation Statistics · 886 operations, July 2023 – July 2026 · If WN1636 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
What stands out
How WN1636 compares to other flight numbers, not just to itself.
Every day of the week performs about the same on this flight, steadier than 99% of 1,710 comparable flight numbers.
94.9% on time on the best day (Thursday) against 92.7% on the worst (Monday).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · The one thing about this specific departure that ranks most extreme against every other published flight number, out of everything FlyerIntel checks — shown only when something clears a real statistical bar, not for every flight.
Where WN1636 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
Ask for the position of WN1636 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.
Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| WN1636 | 94.4% | 1.02% | -11 min | 1.1% | 886 |
| Southwest Airlines on HOU → DAL | 81.3% | 2.07% | -8 min | 6.1% | 12,672 |
| All HOU → DAL flights | 81.3% | 2.07% | -8 min | 6.1% | 12,672 |
WN1636 has cancelled 1.02% of its scheduled departures (9 of 886), against 2.07% for all HOU → DAL flights — this specific departure cancels 1.1 percentage points less often than the route as a whole. Different flight numbers on the same route can carry different aircraft, crews and schedules, so this is a fact about WN1636 specifically, not about the route it flies.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why WN1636 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for WN1636 on HOU → DAL. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies WN1636 comes in late, and what that does to the departure.
WN1636 is usually the aircraft’s first flight of the day: the schedule gives it a median of 7.6 hours on the ground at HOU, so its “inbound” is mostly the aircraft’s arrival the evening before.
When the aircraft came in 15 or more minutes late, WN1636 pushed back an average of 1 minute early; when it came in on time or early, an average of 0 minutes early.
Each departure is matched to the flight the same aircraft flew into HOU just before it, using the tail number in the DOT file, 761 of 877 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| WN1636 | 37% | 5% | 5% |
| Network, same turn | 29% | 12% | 9% |
A night on the ground absorbs most of a late arrival, so a late inbound matters far less on a turn this long than on a same-day one.
The network row is every flight with a scheduled turn of 6 hours or more, usually overnight. How often WN1636’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often WN1636 left 15 or more minutes late is lower than the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
From pushback to gate
When it leaves HOU late, does that still matter by the time it reaches DAL?
WN1636 pushes back an average of 0.7 minutes early and reaches the gate at DAL an average of 7.0 minutes early. The 6.2 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 10.8 minutes on the taxiways at HOU, 1.0 minutes shorter than a typical HOU departure in the same hour.
On arrival at DAL, WN1636 spends 4.8 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is about what any arrival at DAL spends on the ground before reaching the gate.
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached DAL. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 8,904 departures from HOU scheduled in the clock hour WN1636 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at DAL (224,035 flights), not just WN1636’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves HOU
Part of any flight’s record belongs to the clock rather than to the flight. WN1636 has one departure time, so this is what that time is worth.
On-time arrival rate. 8,904 departures from HOU are scheduled in the 6 AM–7 AM hour over the period, against 172,224 across the whole day.
WN1636 is scheduled out of HOU at 6:00 AM, in the 6 AM–7 AM bank. Departures from HOU in that hour arrive on time 93.4% of the time against 78.8% across the airport’s whole day — the slot alone is worth 14.5 points better before anything about this particular flight is considered.
The two airport figures cover every departure from HOU to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does WN1636 run worse on particular days?
Thursday is historically the most reliable day and Monday the least, a gap of 2.2 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.
Other routes WN1636 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| DAL→BHM Dallas to Birmingham | April 12, 2026 – May 31, 2026 | 7 | — |
| DAL→PDX Dallas to Portland | March 5, 2026 – April 6, 2026 | 15 | — |
| DAL→LGA Dallas to New York | March 8, 2026 – April 5, 2026 | 5 | — |
| DAL→PHL Dallas to Philadelphia | March 7, 2026 – April 4, 2026 | 13 | — |
| DAL→IND Dallas to Indianapolis | February 12, 2026 – March 1, 2026 | 8 | — |
| DAL→SAN Dallas to San Diego | November 3, 2025 – December 31, 2025 | 23 | — |
| DAL→LAS Dallas to Las Vegas | September 7, 2023 – October 29, 2025 | 57 | — |
| DAL→SMF Dallas to Sacramento | June 5, 2025 – August 4, 2025 | 26 | — |
| LAS→BHM Las Vegas to Birmingham | June 5, 2025 – August 4, 2025 | 26 | — |
| LGB→LAS Long Beach to Las Vegas | June 5, 2025 – August 4, 2025 | 26 | — |
| SMF→LGB Sacramento to Long Beach | June 5, 2025 – August 4, 2025 | 26 | — |
| DAL→BNA Dallas to Nashville | April 8, 2025 – June 4, 2025 | 18 | — |
| DAL→MCI Dallas to Kansas City | December 1, 2024 | 1 | — |
| DAL→ELP Dallas to El Paso | June 9, 2024 – August 4, 2024 | 9 | — |
| LAS→PHX Las Vegas to Phoenix | June 4, 2024 – July 31, 2024 | 18 | — |
| PHX→AUS Phoenix to Austin | June 4, 2024 – July 31, 2024 | 18 | — |
| DAL→DEN Dallas to Denver | July 5, 2024 | 1 | — |
| DEN→TUS Denver to Tucson | July 5, 2024 | 1 | — |
| TUS→LAS Tucson to Las Vegas | July 5, 2024 | 1 | — |
| LAS→PSP Las Vegas to Palm Springs | July 4, 2024 | 1 | — |
| PSP→SMF Palm Springs to Sacramento | July 4, 2024 | 1 | — |
| DAL→OMA Dallas to Omaha | March 9, 2024 – April 6, 2024 | 5 | — |
| OMA→DEN Omaha to Denver | March 9, 2024 – April 6, 2024 | 5 | — |
| DAL→SJC Dallas to San Jose | March 12, 2024 – April 3, 2024 | 8 | — |
| DAL→STL Dallas to St. Louis | October 5, 2023 – November 3, 2023 | 14 | — |
| DAL→MDW Dallas to Chicago | October 10, 2023 – November 1, 2023 | 8 | — |
| DAL→PHX Dallas to Phoenix | July 3, 2023 – October 4, 2023 | 16 | — |
| PHX→RNO Phoenix to Reno | September 5, 2023 – October 4, 2023 | 10 | — |
| BUR→SJC Burbank to San Jose | September 7, 2023 – October 2, 2023 | 12 | — |
| LAS→BUR Las Vegas to Burbank | September 7, 2023 – October 2, 2023 | 12 | — |
| SJC→GEG San Jose to Spokane | September 7, 2023 – October 2, 2023 | 12 | — |
| BWI→BOS Baltimore to Boston | August 15, 2023 – September 4, 2023 | 17 | — |
| DAL→BWI Dallas to Baltimore | August 15, 2023 – September 4, 2023 | 17 | — |
Because the same number has served different journeys, the statistics above describe only the route WN1636 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
3 min late
against a median of 11 min early
Percentiles over 886 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| WN4 | Southwest Airlines | 95.2% | 12 min early | 659 |
| WN1636 this flight | Southwest Airlines | 94.4% | 11 min early | 886 |
| WN34 | Southwest Airlines | 77.7% | 4 min early | 717 |
| WN52 | Southwest Airlines | 73.5% | 5 min early | 739 |
| WN54 | Southwest Airlines | 72.9% | 4 min early | 619 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. WN1636 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 886 records of WN1636 operating HOU → DAL, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed