Route reliability record
COS→ORD
Colorado Springs to Chicago
- Flights
- 1,001
- Period
- July 2025 to June 2026
- Distance
- 911 mi
- Carriers
- 2
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land close to two hours behind schedule. That rests on 1,001 COS to ORD flights, with a median arrival 8 minutes early.
Best time to fly COS to ORD: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 88.1% of the time and Saturday flights 82.5%, against 74.6% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.6%
Arrivals under 15 minutes late, of 973 completed flights
Avg delay
112 min
Across delayed arrivals only, not all flights
Cancelled
1.90%
National rate is 1.81%
Best carrier
SkyWest
73.3% on time across 821 flights
These figures cover 1,001 flights between July 2025 and June 2026. Beyond the headline rate, 12.0% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on COS to ORD
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 |
|---|---|---|---|---|---|
| United Airlinesthin sample | 180 | 80.6% | 62 min | 1.11% | B |
| SkyWest Airlines | 821 | 73.3% | 120 min | 2.07% | C |
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 18 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–8am195 flights88.1%
- 8am–11am88 flights80.5%
- 11am–2pm716 flights70.0%
- 2pm–5pm2 flights—
- 5pm–8pm—
- 8pm–5am—
Scale runs 60% to 95%. 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 70.0% on time against 88.1% for 5am–8am. 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 11am–2pm window is the busiest, with 716 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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.
May is the best month on the calendar at 84.8% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 94 flights.
Across the week, Saturday is the strongest day at 82.5% on time and Sunday the weakest at 68.1%. 14 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 50% of the 28,000 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.
- 50%Carrier
- 28%Late-arriving aircraft
- 19%National Airspace System
- 4%Extreme weather
The largest share of delay minutes, 50%, 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 14,000 of the 28,000 delay minutes reported here. The split is drawn from 27,650 reported delay minutes.
Cancellations sit at 1.90% against a national 1.81%, which is ordinary. Diversions add another 0.90%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.0% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 911 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 69.7% on time across 1,001 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.
One caution: this is a thin sample. 1,001 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 ORD after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,001 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 74.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 973 completed flights over 12 months sit behind that.
Common questions
COS to ORD questions
How often is COS to ORD delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.4% of the 1,001 flights in this analysis, against 22.4% nationally. Delayed flights are late by close to two hours on average.
How reliable is COS to ORD compared with the rest of the country?
74.6% of flights arrive on time here against a national 77.6%, a difference of 3 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on COS to ORD?
The 5am–8am departure window is the strongest at 88.1% on time. The 11am–2pm window is the weakest at 70.0%, 18 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 March delays on COS to ORD?
March is the weakest month at 61.0% on time, compared with 84.8% in May. Across the year that is 24 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
- ORD to COS — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on COS to ORD80.6%
- SkyWest Airlines on COS to ORD73.3%
- COS to DEN, a related route78.8%
- LGA to ORD, a related route67.3%
- COS to DFW, a related route77.8%
- United Airlines on-time record80.6%
- SkyWest Airlines on-time record73.3%
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.04 million flight records
Direction matters. COS to ORD and ORD 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.