Route reliability record
ORD→COS
Chicago to Colorado Springs
- 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. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 1,001 ORD to COS flights, with a median arrival right on schedule.
Best time to fly ORD to COS: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 72.9% of the time and Wednesday flights 75.5%, against 69.7% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 8 points behind the country as a whole. Across a thousand flights that is about 79 extra late arrivals.
Key figures
On time
69.7%
Arrivals under 15 minutes late, of 976 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
2.00%
National rate is 1.81%
Best carrier
SkyWest
66.8% on time across 822 flights
These figures cover 1,001 flights between July 2025 and June 2026. Beyond the headline rate, 11.1% 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 ORD to COS
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 | 179 | 82.6% | 58 min | 0.56% | B+ |
| SkyWest Airlines | 822 | 66.8% | 73 min | 2.31% | C |
Flight by flight
Flights on ORD to COS
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 17 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–11am719 flights72.9%
- 11am–2pm1 flights—
- 2pm–5pm3 flights—
- 5pm–8pm125 flights55.5%
- 8pm–5am153 flights64.6%
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 55.5% on time, against 72.9% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 719 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 34 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.
December is the weak month at 52.8% on time, against 86.5% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 93 flights.
Across the week, Wednesday is the strongest day at 75.5% on time and Friday the weakest at 59.0%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 21,000 reported delay minutes.
- 39%Carrier
- 28%Late-arriving aircraft
- 19%National Airspace System
- 14%Extreme weather
Extreme weather accounts for 14% 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 2.2 times the usual weather exposure. The split is drawn from 21,122 reported delay minutes.
The largest share of delay minutes, 39%, 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 8,208 of the 21,000 delay minutes reported here.
Cancellations sit at 2.00% against a national 1.81%, which is ordinary. Diversions add another 0.50%.
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. 11.1% 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 74.6% on time across 1,001 flights, 5 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 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 COS 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 69.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 976 completed flights over 12 months sit behind that.
Common questions
ORD to COS questions
How often is ORD to COS delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 30.3% of the 1,001 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is ORD to COS compared with the rest of the country?
69.7% of flights arrive on time here against a national 77.6%, a difference of 8 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on ORD to COS?
The 8am–11am departure window is the strongest at 72.9% on time. The 5pm–8pm window is the weakest at 55.5%, 17 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 December delays on ORD to COS?
December is the weakest month at 52.8% on time, compared with 86.5% in September. Across the year that is 34 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
- COS to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on ORD to COS82.6%
- SkyWest Airlines on ORD to COS66.8%
- ORD to LGA, a related route67.3%
- DEN to COS, a related route75.8%
- ORD to BOS, a related route67.6%
- United Airlines on-time record82.6%
- SkyWest Airlines on-time record66.8%
- 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. ORD to COS and COS to ORD 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.