Carrier route record
DLSLC→GEG
Delta Air Lines · Salt Lake City to Spokane
- Flights
- 927
- Period
- July 2025 to June 2026
- Share of route
- 56%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on SLC to GEG lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 927 flights, with a median arrival 7 minutes early.
Set against the rest of the country, Delta's SLC to GEG record is 4 points better than the US average of 77.6%. That gap is worth roughly 42 fewer late arrivals for every thousand flights.
Key figures
On time
81.8%
Arrivals under 15 minutes late, of 918 completed flights
Avg delay
80 min
Across delayed arrivals only, not all flights
Cancelled
0.76%
National rate is 1.81%
Whole route
86.7%
Every carrier on SLC to GEG, 1,666 flights
These figures cover 927 flights between July 2025 and June 2026. The median arrival is 7 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
Delta against every carrier on SLC to GEG
Delta flew 927 of the 1,666 flights on SLC to GEG, most of the route. Its 81.8% on time is 5 points worse than the route as a whole, which runs 86.7%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 92.9% to Delta at 81.8%.
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 Airlines | 739 | 92.9% | 57 min | 0.14% | A+ |
| Delta Air Lines (this page) | 927 | 81.8% | 80 min | 0.76% | B+ |
Flight by flight
Delta flight numbers on SLC to GEG
Departure window
When Delta runs best on this route
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 927 flights.
- 5am–8am—
- 8am–11am12 flights—
- 11am–2pm338 flights84.2%
- 2pm–5pm194 flights79.6%
- 5pm–8pm19 flights—
- 8pm–5am364 flights80.9%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 84.2% on time. The full set of windows spans 5 points.
Across the year
Delta on SLC to GEG through the year
August is the worst month at 76.7% on time, 14 points below March, the best at 90.3%. 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. June was the busiest month here, with 108 flights.
Across the week, Wednesday is the strongest day at 85.0% on time and Sunday the weakest at 78.8%. 6 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Carrier accounts for 69% 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.
- 69%Carrier
- 17%Late-arriving aircraft
- 8%Extreme weather
- 6%National Airspace System
The largest share of delay minutes, 69%, 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 9,213 of the 13,000 delay minutes reported here. The split is drawn from 13,318 reported delay minutes.
Cancellations are rare at 0.76%, 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 costs
5.4% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
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 88.1% on time across 927 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 927 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 Delta on SLC to GEG
Put together: treat all of this as provisional. 927 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 81.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 918 completed flights over 12 months sit behind that.
Related
Where to go next
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.