Route reliability record
COS→SLC
Colorado Springs to Salt Lake City
- Flights
- 716
- Period
- July 2025 to June 2026
- Distance
- 411 mi
- Carriers
- 1
This route earns an A+. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 716 COS to SLC flights, with a median arrival 14 minutes early.
Best time to fly COS to SLC: a 8am–11am departure, ideally on a Monday. Flights in that window arrived on time 96.4% of the time and Monday flights 95.2%, against 93.1% for the route overall.
Set against the rest of the country, this route's record is 16 points better than the US average of 77.6%. That gap is worth roughly 155 fewer late arrivals for every thousand flights.
Key figures
On time
93.1%
Arrivals under 15 minutes late, of 714 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.14%
National rate is 1.81%
Best carrier
SkyWest
93.1% on time across 716 flights
These figures cover 716 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 COS to SLC
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 | 716 | 93.1% | 63 min | 0.14% | A+ |
Flight by flight
Flights on COS 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.
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 half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am365 flights96.4%
- 11am–2pm153 flights94.1%
- 2pm–5pm—
- 5pm–8pm198 flights86.2%
- 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 96.4% of the time, against 86.2% for the evening window. That is 10 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 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.
July is the worst month at 82.1% on time, 18 points below October, the best at 100.0%. 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. March was the busiest month here, with 62 flights.
Across the week, Monday is the strongest day at 95.2% on time and Sunday the weakest at 90.3%. 5 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. Extreme weather accounts for 49% of the 3,093 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.
- 49%Extreme weather
- 47%Carrier
- 4%National Airspace System
Extreme weather accounts for 49% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 7.9 times the usual weather exposure. The split is drawn from 3,093 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 1,458 of the 3,093 delay minutes reported here.
Cancellations are rare at 0.14%, 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 2.0% 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.
At 411 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg runs 91.4% on time across 716 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 716 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.
Work out the risk of missing a connection in SLC after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 716 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 93.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 714 completed flights over 12 months sit behind that.
Common questions
COS to SLC questions
How often is COS to SLC delayed?
About one flight in fifteen arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 6.9% of the 716 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is COS to SLC compared with the rest of the country?
93.1% of flights arrive on time here against a national 77.6%, a difference of 16 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on COS to SLC?
The 8am–11am departure window is the strongest at 96.4% on time. The 5pm–8pm window is the weakest at 86.2%, 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 July delays on COS to SLC?
July is the weakest month at 82.1% on time, compared with 100.0% in October. Across the year that is 18 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 COS — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- COS to DEN, a related route78.8%
- DEN to SLC, a related route77.5%
- COS to DFW, a related route77.8%
- SkyWest Airlines on-time record93.1%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. COS to SLC and SLC to COS 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.