Route reliability record
ORD→GRB
Chicago to Green Bay
- Flights
- 2,775
- Period
- July 2025 to June 2026
- Distance
- 173 mi
- Carriers
- 3
This route carries a cancellation problem, not just a delay problem: 4.3% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, about seven flights in ten arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 2,775 flights, of which Envoy Air flew 1,375 at 74.3% on time.
The national on-time rate over the same period is 77.6%, so this route runs 9 points behind the country as a whole. Across a thousand flights that is about 88 extra late arrivals.
Key figures
On time
68.8%
Arrivals under 15 minutes late, of 2,652 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
4.29%
National rate is 1.81%
Best carrier
Envoy
74.3% on time across 1,375 flights
These figures cover 2,775 flights between July 2025 and June 2026. Beyond the headline rate, 12.6% 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 GRB
The choice of carrier is not cosmetic here. Envoy Air arrives on time 74.3% of the time; SkyWest Airlines manages 61.2%. Sample sizes sit next to every figure, because a two-point gap across 1,234 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 166 | 79.1% | 108 min | 4.82% | B− |
| Envoy Air | 1,375 | 74.3% | 66 min | 3.71% | C− |
| SkyWest Airlines | 1,234 | 61.2% | 85 min | 4.86% | D− |
SkyWest Airlines cancels 4.9% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
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 19 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am720 flights80.1%
- 11am–2pm366 flights72.8%
- 2pm–5pm559 flights62.1%
- 5pm–8pm542 flights61.5%
- 8pm–5am588 flights65.3%
Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.5% on time, against 80.1% 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 720 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 35 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 50.8% on time, against 85.4% in October. 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. April was the busiest month here, with 312 flights.
Across the week, Saturday is the strongest day at 73.1% on time and Sunday the weakest at 64.3%. 9 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 65,000 reported delay minutes.
- 39%Late-arriving aircraft
- 27%Carrier
- 20%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 64,663 reported delay minutes.
39% 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 65,000 reported delay minutes here, that single category outweighs weather by 3 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.
Cancellations run at 4.29%, against 1.81% nationally. That is about one flight in 25 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
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. 12.6% 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.
At 173 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 71.1% on time across 2,776 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.
The sample behind these figures is 2,775 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 delay figures matter less here than the 4.29% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,652 completed flights over 12 months sit behind that.
Common questions
ORD to GRB questions
How often is ORD to GRB delayed?
About one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 31.2% of the 2,775 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ORD to GRB?
Envoy Air leads at 74.3% on time across 1,375 flights. SkyWest Airlines is at the other end on 61.2%, a gap of 13 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 GRB?
The 8am–11am departure window is the strongest at 80.1% on time. The 5pm–8pm window is the weakest at 61.5%, 19 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 GRB?
December is the weakest month at 50.8% on time, compared with 85.4% in October. Across the year that is 35 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
- GRB to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on-time record79.1%
- Envoy Air on-time record74.3%
- SkyWest Airlines on-time record61.2%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. ORD to GRB and GRB 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.