Carrier route record

WNGEG→DEN

Southwest Airlines · Spokane to Denver

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 GEG to DEN lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That rests on 859 flights, with a median arrival 5 minutes early.

Set against the rest of the country, Southwest's GEG to DEN record is 5 points better than the US average of 77.3%. That gap is worth roughly 51 fewer late arrivals for every thousand flights.

On time

82.4%

Arrivals under 15 minutes late, of 851 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.12%

National rate is 1.89%

Whole route

84.2%

Every carrier on GEG to DEN, 2,042 flights

These figures cover 859 flights between September 2025 and August 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

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Carrier by carrier

Southwest against every carrier on GEG to DEN

Southwest flew 859 of the 2,042 flights on GEG to DEN, about 42% of it. Its 82.4% on time is 2 points worse than the route as a whole, which runs 84.2%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 86.3% to Frontier at 80.6%. 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.

On-time performance by carrier on GEG to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	258	86.3%	98 min	1.16%	A
United Airlines	826	85.8%	86 min	0.36%	A+
Southwest Airlines (this page)	859	82.4%	54 min	0.12%	B+
Frontier Airlinesthin sample	99	80.6%	32 min	0.00%	B+

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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 34 points, against half a point between the best and worst carrier.

5am–8am360 flights96.1%
8am–11am52 flights94.2%
11am–2pm203 flights79.1%
2pm–5pm244 flights62.1%
5pm–8pm—
8pm–5am—

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.1% of the time, against 62.1% for the afternoon window. That is 34 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 360 flights scheduled in it.

Across the year

Southwest on GEG to DEN through the year

Darker means more delays. Figures are on-time percentages.November best, June worst

July is the worst month at 74.7% on time, 21 points below November, the best at 95.2%. 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. July was the busiest month here, with 93 flights.

Across the week, Sunday is the strongest day at 90.8% on time and Tuesday the weakest at 75.4%, a spread of 15 points.

Arrival by arrival

How late Southwest on GEG to DEN runs when it is late

The 150 late arrivals split 55 under half an hour, 55 between 30 and 60 minutes, and 40 an hour or more.

15+ min early194 flights22.8%
Within 15 min507 flights59.6%
15–29 min late55 flights6.5%
30–59 min late55 flights6.5%
1–2 hours late26 flights3.1%
2+ hours late14 flights1.6%

Scale runs 0% to 100%.

Share of 851 completed flights by arrival against schedule.

A late pushback is often recovered here: of 198 departures that left 15 minutes late or more, 64 still arrived on time. Only 16 left on time and still arrived late.

The worst days

Worst days for Southwest on GEG to DEN

The latest arrival of the period was on 14 January 2026, 5 hours 4 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across January, August, December, July and April, with no single month standing out.

The latest arrivals of Southwest on GEG to DEN in the period
Date	Arrived late by	Largest filed cause
14 January 2026	5 hours 4 minutes	Late-arriving aircraft
14 August 2026	4 hours 50 minutes	National Airspace System
20 December 2025	4 hours 7 minutes	Late-arriving aircraft
8 July 2026	4 hours 2 minutes	Carrier
4 April 2026	3 hours 21 minutes	National Airspace System

Delay causes

Why Southwest runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 8,129 reported delay minutes.

Late-arriving aircraft
41%
National Airspace System
39%
Carrier
19%
Extreme weather
2%

41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,129 reported delay minutes here, that single category outweighs weather by 26 to one. The split is drawn from 8,129 reported delay minutes.

39% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,144 minutes out of 8,129, against a national NAS share of 21%.

Cancellations are rare at 0.12%, 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

Badly late arrivals are rare here: only 4.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

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 69.8% on time across 859 flights, 13 points below 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 GEG to DEN

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 82.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 851 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures