Carrier route record
WNDEN→GEG
Southwest Airlines · Denver to Spokane
- Flights
- 859
- Period
- September 2025 to August 2026
- Share of route
- 42%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to GEG sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 859 flights, with a median arrival 2 minutes late.
The national on-time rate over the same period is 77.3%, so Southwest on DEN to GEG runs 8 points behind the country as a whole. Across a thousand flights that is about 75 extra late arrivals.
Key figures
On time
69.8%
Arrivals under 15 minutes late, of 854 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Whole route
76.3%
Every carrier on DEN to GEG, 2,042 flights
These figures cover 859 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Carrier by carrier
Southwest against every carrier on DEN to GEG
Southwest flew 859 of the 2,042 flights on DEN to GEG, about 42% of it. Its 69.8% on time is 7 points worse than the route as a whole, which runs 76.3%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 89.4% to Southwest at 69.8%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 258 | 89.4% | 50 min | 0.78% | A+ |
| Frontier Airlinesthin sample | 99 | 88.9% | 32 min | 0.00% | A+ |
| United Airlines | 826 | 77.6% | 63 min | 0.24% | B+ |
| Southwest Airlines (this page) | 859 | 69.8% | 47 min | 0.47% | C+ |
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Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against half a point between the best and worst carrier.
- 5am–8am41 flights87.8%
- 8am–11am321 flights86.9%
- 11am–2pm23 flights—
- 2pm–5pm106 flights67.9%
- 5pm–8pm28 flights—
- 8pm–5am340 flights52.7%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 52.7% on time, against 87.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 340 flights scheduled in it.
Across the year
Southwest on DEN to GEG through the year
Delays peak in March, when the on-time rate falls to 55.7%. January is the strongest month at 83.9%. Moving a flexible trip across that boundary buys 28 points. July was the busiest month here, with 93 flights.
Across the week, Tuesday is the strongest day at 74.8% on time and Friday the weakest at 64.5%, a spread of 10 points.
Arrival by arrival
How late Southwest on DEN to GEG runs when it is late
The 258 late arrivals split 95 under half an hour, 99 between 30 and 60 minutes, and 64 an hour or more.
- 15+ min early92 flights10.8%
- Within 15 min504 flights59.0%
- 15–29 min late95 flights11.1%
- 30–59 min late99 flights11.6%
- 1–2 hours late54 flights6.3%
- 2+ hours late10 flights1.2%
Scale runs 0% to 100%.
Share of 854 completed flights by arrival against schedule.
66 of 298 late departures made up the time and arrived on time, 22% of them. 26 flights left on time and still arrived late.
The worst days
Worst days for Southwest on DEN to GEG
The latest arrival of the period was on 12 June 2026, 3 hours 42 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 12 June 2026 | 3 hours 42 minutes | Late-arriving aircraft |
| 10 March 2026 | 3 hours 23 minutes | Late-arriving aircraft |
| 15 March 2026 | 3 hours 14 minutes | Late-arriving aircraft |
| 28 July 2026 | 2 hours 44 minutes | Late-arriving aircraft |
| 19 May 2026 | 2 hours 39 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 55% of the 12,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Late-arriving aircraft
- 31%Carrier
- 12%National Airspace System
- 2%Extreme weather
55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 12,000 reported delay minutes here, that single category outweighs weather by 30 to one. The split is drawn from 12,044 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.8% on time here.
Cancellations are rare at 0.47%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
7.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 45 minutes, which a normal layover absorbs.
The 836 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 82.4% on time across 859 flights, 13 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 13 points of difference.
One caution: this is a thin sample. 859 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DEN to GEG
Put together: treat all of this as provisional. 859 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 69.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 854 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to GEG, every carrier
- Southwest on GEG to DEN, the return leg
- SkyWest Airlines on DEN to GEG89.4%
- United Airlines on DEN to GEG77.6%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.