Route reliability record
ORD→ROC
Chicago to Rochester
- Flights
- 2,320
- Period
- July 2025 to June 2026
- Distance
- 528 mi
- Carriers
- 4
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 about an hour behind schedule. That rests on 2,320 flights, of which Republic Airways flew 695 at 80.2% on time.
Republic Airways is the most reliable of the three carriers covered here at 80.2% on time across 695 flights.
Key figures
On time
74.2%
Arrivals under 15 minutes late, of 2,261 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
2.24%
National rate is 1.81%
Best carrier
Republic
80.2% on time across 695 flights
These figures cover 2,320 flights between July 2025 and June 2026. Beyond the headline rate, 9.1% 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 ROC
The choice of carrier is not cosmetic here. Republic Airways arrives on time 80.2% of the time; United Airlines manages 63.2%. Sample sizes sit next to every figure, because a two-point gap across 587 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 695 | 80.2% | 67 min | 2.16% | B |
| Envoy Air | 813 | 80.1% | 62 min | 2.34% | B |
| SkyWest Airlinesthin sample | 225 | 63.6% | 68 min | 4.44% | D− |
| United Airlines | 587 | 63.2% | 66 min | 1.36% | D |
The spread between Republic and United is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.
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 23 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am177 flights86.9%
- 8am–11am575 flights82.9%
- 11am–2pm221 flights85.3%
- 2pm–5pm577 flights66.8%
- 5pm–8pm501 flights64.0%
- 8pm–5am269 flights72.4%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.0% on time, against 86.9% for the 5am–8am 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 2pm–5pm window is the busiest, with 577 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 17 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.
February is the weak month at 65.0% on time, against 82.2% in May. 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. November was the busiest month here, with 225 flights.
Across the week, Thursday is the strongest day at 78.1% on time and Sunday the weakest at 65.8%. 12 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. Late-arriving aircraft accounts for 46% of the 38,000 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.
- 46%Late-arriving aircraft
- 27%Carrier
- 20%National Airspace System
- 7%Extreme weather
46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 38,000 reported delay minutes here, that single category outweighs weather by 7 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 38,058 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.9% on time here.
Cancellations sit at 2.24% against a national 1.81%, which is ordinary. Diversions add another 0.30%.
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. 9.1% 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 528 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 runs 74.7% on time across 2,340 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,320 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.
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 82.2% on time and February 65.0%, a swing of 17 points. If the dates move at all, move them out of February before you think about anything else. 2,261 completed flights over 12 months sit behind that.
Common questions
ORD to ROC questions
How often is ORD to ROC delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.8% of the 2,320 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ORD to ROC?
Republic Airways leads at 80.2% on time across 695 flights. United Airlines is at the other end on 63.2%, a gap of 17 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 ORD to ROC?
The 5am–8am departure window is the strongest at 86.9% on time. The 5pm–8pm window is the weakest at 64.0%, 23 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 February delays on ORD to ROC?
February is the weakest month at 65.0% on time, compared with 82.2% in May. Across the year that is 17 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
- ROC to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on-time record80.2%
- Envoy Air on-time record80.1%
- SkyWest Airlines on-time record63.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. ORD to ROC and ROC to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.