Route reliability record
GEG→SLC
Spokane to Salt Lake City
- Flights
- 1,668
- Period
- September 2025 to August 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 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 1,668 GEG to SLC flights, of which SkyWest Airlines flew 694 at 94.1% on time.
Best time to fly GEG to SLC: a 8am–11am departure, ideally on a Thursday. Flights in that window arrived on time 95.7% of the time and Thursday flights 92.9%, against 90.4% for the route overall.
Set against the rest of the country, this route's record is 13 points better than the US average of 77.3%. That gap is worth roughly 131 fewer late arrivals for every thousand flights.
Key figures
On time
90.4%
Arrivals under 15 minutes late, of 1,656 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
0.60%
National rate is 1.89%
Best carrier
SkyWest
94.1% on time across 694 flights
These figures cover 1,668 flights between September 2025 and August 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.
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Carrier by carrier
Which airline is most reliable on GEG to SLC
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 94.1% of the time; Delta Air Lines manages 87.8%. Sample sizes sit next to every figure, because a two-point gap across 974 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 694 | 94.1% | 73 min | 0.43% | A+ |
| Delta Air Lines | 974 | 87.8% | 83 min | 0.72% | A+ |
SkyWest leads Delta by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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.
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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 | 93.7% | 94.1% | 0.43% | 8am–11am, Wed | — |
| 2. GEG → SLCSpokane to Salt Lake City | Delta Air Lines | 87.2% | 87.8% | 0.72% | 5am–8am, Thu | DL 1440 06:00 |
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 10 points, against 6 points between the best and worst carrier.
- 5am–8am365 flights92.5%
- 8am–11am348 flights95.7%
- 11am–2pm329 flights85.7%
- 2pm–5pm108 flights86.7%
- 5pm–8pm518 flights89.1%
- 8pm–5am—
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 85.7% on time against 95.7% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5pm–8pm window is the busiest, with 518 flights scheduled in it.
Explore
Filter GEG to SLC 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 GEG to SLC, the best departure window is 8am–11am at 95.7% on time and the worst is 11am–2pm at 85.7%, a wide gap of 10.0 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am92.5%
- 8–11am95.7%
- 11am–2pm85.7%
- 2–5pm86.7%
- 5–8pm89.1%
- 8pm–5am—
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 12 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.
August is the worst month at 83.0% on time, 12 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. July was the busiest month here, with 151 flights.
Across the week, Thursday is the strongest day at 92.9% on time and Saturday the weakest at 86.1%, a spread of 7 points.
Delay causes
Why this route gets delayed
Carrier accounts for 44% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Carrier
- 41%Late-arriving aircraft
- 11%Extreme weather
- 4%National Airspace System
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 13,000 reported delay minutes here, that single category outweighs weather by 4 to one. The split is drawn from 12,779 reported delay minutes.
The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 5,591 of the 13,000 delay minutes reported here.
Cancellations are rare at 0.60%, 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
Badly late arrivals are rare here: only 3.6% 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 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.
The return leg is a different operation and performs like one: it runs 85.9% on time across 1,668 flights, 5 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 5 points of difference.
The sample behind these figures is 1,668 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: the calendar is the biggest lever here, not the carrier or the hour. May runs 95.3% on time and August 83.0%, a swing of 12 points. If the dates move at all, move them out of August before you think about anything else. 1,656 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 9.6% of the 1,668 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on GEG to SLC?
SkyWest Airlines leads at 94.1% on time across 694 flights. Delta Air Lines is at the other end on 87.8%, 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 95.7% on time. The 11am–2pm window is the weakest at 85.7%, 10 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 83.0% on time, compared with 95.3% in May. Across the year that is 12 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 SLC94.1%
- Delta Air Lines on GEG to SLC87.8%
- GEG to SEA, a related route85.7%
- DEN to SLC, a related route78.2%
- GEG to DEN, a related route84.2%
- SkyWest Airlines on-time record94.1%
- Delta Air Lines on-time record87.8%
- Why the first flight of the morning is statistically safest
- The most punctual routes in the US, and the least
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.