Route reliability record
GEG→SLC
Spokane to Salt Lake City
- Flights
- 1,666
- Period
- July 2025 to June 2026
- Distance
- 546 mi
- Carriers
- 2
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,666 GEG to SLC flights, of which SkyWest Airlines flew 739 at 93.7% on time.
Best time to fly GEG to SLC: a 8am–11am departure, ideally on a Thursday. Flights in that window arrived on time 95.9% of the time and Thursday flights 93.7%, against 90.6% for the route overall.
Set against the rest of the country, this route's record is 13 points better than the US average of 77.6%. That gap is worth roughly 130 fewer late arrivals for every thousand flights.
Key figures
On time
90.6%
Arrivals under 15 minutes late, of 1,653 completed flights
Avg delay
85 min
Across delayed arrivals only, not all flights
Cancelled
0.66%
National rate is 1.81%
Best carrier
SkyWest
93.7% on time across 739 flights
These figures cover 1,666 flights between July 2025 and June 2026. The median arrival is 14 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.
Carrier by carrier
Which airline is most reliable on GEG to SLC
The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 739 | 93.7% | 72 min | 0.41% | A+ |
| Delta Air Lines | 927 | 88.1% | 91 min | 0.86% | A+ |
No carrier stands out. SkyWest tops the table at 93.7%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on GEG to SLC
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.
Best ways to make this trip
The most reliable ways to fly Spokane to Salt Lake City
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. GEG → SLCSpokane to Salt Lake City | SkyWest Airlines | 93.3% | 93.7% | 0.41% | 8am–11am, Wed | — |
| 2. GEG → SLCSpokane to Salt Lake City | Delta Air Lines | 87.3% | 88.1% | 0.86% | 5am–8am, Thu | DL 1440 05:45 |
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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,666 flights.
- 5am–8am365 flights92.0%
- 8am–11am348 flights95.9%
- 11am–2pm329 flights87.2%
- 2pm–5pm108 flights86.7%
- 5pm–8pm516 flights89.1%
- 8pm–5am—
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 95.9% of the time, against 86.7% for the afternoon window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 516 flights scheduled in it.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 1,666 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
August is the worst month at 84.5% on time, 11 points below May, the best at 95.3%. 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. May was the busiest month here, with 149 flights.
Across the week, Thursday is the strongest day at 93.7% on time and Friday the weakest at 87.6%. 6 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 47% of the 13,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 47%Carrier
- 39%Late-arriving aircraft
- 10%Extreme weather
- 4%National Airspace System
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 13,000 reported delay minutes here, that single category outweighs weather by 4 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 13,220 reported delay minutes.
The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 6,257 of the 13,000 delay minutes reported here.
Cancellations are rare at 0.66%, below the national 1.81% 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
Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 8.1% 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 546 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 86.7% on time across 1,666 flights, 4 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 4 points of difference.
The sample behind these figures is 1,666 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 SLC after this flight
What to do with this
Booking this route
Put together: take the 8am–11am departure, avoid August if the dates are flexible, and if two carriers are within a few dollars of each other, SkyWest is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 9 points, which is the most any booking decision can do. 1,653 completed flights over 12 months sit behind that.
Common questions
GEG to SLC questions
How often is GEG to SLC delayed?
About one flight in ten arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 9.4% of the 1,666 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on GEG to SLC?
SkyWest Airlines leads at 93.7% on time across 739 flights. Delta Air Lines is at the other end on 88.1%, a gap of 6 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 GEG to SLC?
The 8am–11am departure window is the strongest at 95.9% on time. The 2pm–5pm window is the weakest at 86.7%, 9 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 August delays on GEG to SLC?
August is the weakest month at 84.5% on time, compared with 95.3% in May. Across the year that is 11 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
- SLC to GEG — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- SkyWest Airlines on GEG to SLC93.7%
- Delta Air Lines on GEG to SLC88.1%
- GEG to SEA, a related route85.9%
- DEN to SLC, a related route77.5%
- GEG to DEN, a related route83.8%
- SkyWest Airlines on-time record93.7%
- Delta Air Lines on-time record88.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. GEG to SLC and SLC to GEG 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.