Route reliability record
DEN→GEG
Denver to Spokane
- Flights
- 2,042
- Period
- September 2025 to August 2026
- Distance
- 836 mi
- Carriers
- 4
This route lands a B+, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 2,042 DEN to GEG flights, of which United Airlines flew 826 at 77.6% on time.
Best time to fly DEN to GEG: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 87.8% of the time and Tuesday flights 80.4%, against 76.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.3%
Arrivals under 15 minutes late, of 2,029 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.39%
National rate is 1.89%
Best carrier
United
77.6% on time across 826 flights
These figures cover 2,042 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
Which airline is most reliable on DEN to GEG
The choice of carrier is not cosmetic here. United Airlines arrives on time 77.6% of the time; Southwest Airlines manages 69.8%. Sample sizes sit next to every figure, because a two-point gap across 859 flights means less than a ten-point one.
| 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 | 859 | 69.8% | 47 min | 0.47% | C+ |
United leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on DEN to GEG
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Spokane
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → GEGDenver to Spokane | United Airlines | 77.4% | 77.6% | 0.24% | 11am–2pm, Sat | UA 295 11:15 |
| 2. DEN → GEGDenver to Spokane | Southwest Airlines | 69.5% | 69.8% | 0.47% | 5am–8am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against 8 points between the best and worst carrier.
- 5am–8am41 flights87.8%
- 8am–11am416 flights87.2%
- 11am–2pm729 flights86.0%
- 2pm–5pm122 flights67.2%
- 5pm–8pm392 flights68.7%
- 8pm–5am342 flights53.0%
Scale runs 45% to 95%.
The 8pm–5am window is where this operation falls apart: 53.0% 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 11am–2pm window is the busiest, with 729 flights scheduled in it.
Explore
Filter DEN to GEG by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to GEG, the best departure window is 5am–8am at 87.8% on time and the worst is 8pm–5am at 53.0%, a wide gap of 34.8 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am87.8%
- 8–11am87.2%
- 11am–2pm86.0%
- 2–5pm67.2%
- 5–8pm68.7%
- 8pm–5am53.0%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 23 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 64.9% on time, 23 points below April, the best at 87.9%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 189 flights.
Across the week, Tuesday is the strongest day at 80.4% on time and Friday the weakest at 72.9%, a spread of 8 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 55% of the 25,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Late-arriving aircraft
- 29%Carrier
- 13%National Airspace System
- 2%Extreme weather
- 0%Security
55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 25,000 reported delay minutes here, that single category outweighs weather by 27 to one. The split is drawn from 25,353 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 0.39%, 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 actually costs
6.7% 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 55 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 84.2% on time across 2,042 flights, 8 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 8 points of difference.
The sample behind these figures is 2,042 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in GEG after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 87.9% on time and June 64.9%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 2,029 completed flights over 12 months sit behind that.
Common questions
DEN to GEG questions
How often is DEN to GEG delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.7% of the 2,042 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 55 minutes on average.
Which airline is most reliable on DEN to GEG?
United Airlines leads at 77.6% on time across 826 flights. Southwest Airlines is at the other end on 69.8%, a gap of 8 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DEN to GEG?
The 5am–8am departure window is the strongest at 87.8% on time. The 8pm–5am window is the weakest at 53.0%, 35 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on DEN to GEG?
June is the weakest month at 64.9% on time, compared with 87.9% in April. Across the year that is 23 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- GEG to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on DEN to GEG89.4%
- United Airlines on DEN to GEG77.6%
- Southwest Airlines on DEN to GEG69.8%
- DEN to PHX, a related route75.6%
- SEA to GEG, a related route83.1%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record89.4%
- Frontier Airlines on-time record88.9%
- United Airlines on-time record77.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to GEG and GEG to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.