Route reliability record
GRB→ORD
Green Bay to Chicago
- Flights
- 2,776
- 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 2,776 flights, of which Envoy Air flew 1,375 at 75.1% on time.
The national on-time rate over the same period is 77.6%, so this route runs 7 points behind the country as a whole. Across a thousand flights that is about 65 extra late arrivals.
Key figures
On time
71.1%
Arrivals under 15 minutes late, of 2,653 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
4.25%
National rate is 1.81%
Best carrier
Envoy
75.1% on time across 1,375 flights
These figures cover 2,776 flights between July 2025 and June 2026. Beyond the headline rate, 12.3% 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 GRB to ORD
The choice of carrier is not cosmetic here. Envoy Air arrives on time 75.1% of the time; SkyWest Airlines manages 66.0%. Sample sizes sit next to every figure, because a two-point gap across 1,235 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 166 | 75.6% | 59 min | 5.42% | B− |
| Envoy Air | 1,375 | 75.1% | 69 min | 3.64% | B− |
| SkyWest Airlines | 1,235 | 66.0% | 99 min | 4.78% | C− |
SkyWest Airlines cancels 4.8% 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 30 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am767 flights81.7%
- 8am–11am745 flights76.7%
- 11am–2pm310 flights71.1%
- 2pm–5pm338 flights65.8%
- 5pm–8pm542 flights52.0%
- 8pm–5am74 flights63.3%
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 52.0% on time, against 81.7% 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 5am–8am window is the busiest, with 767 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 20 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 60.3% on time, against 80.3% 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. April was the busiest month here, with 313 flights.
Across the week, Saturday is the strongest day at 76.7% on time and Friday the weakest at 65.3%. 11 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 42% of the 64,000 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.
- 42%Late-arriving aircraft
- 24%National Airspace System
- 20%Carrier
- 13%Extreme weather
- 0%Security
Extreme weather accounts for 13% 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 2.1 times the usual weather exposure. The split is drawn from 64,275 reported delay minutes.
42% 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 64,000 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 4.25%, 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. 12.3% 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 5am–8am window matters as much as it does.
The return leg runs 68.8% on time across 2,775 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 2,776 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 4.25% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,653 completed flights over 12 months sit behind that.
Common questions
GRB to ORD questions
How often is GRB to ORD delayed?
Roughly 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 28.9% of the 2,776 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on GRB to ORD?
Envoy Air leads at 75.1% on time across 1,375 flights. SkyWest Airlines is at the other end on 66.0%, a gap of 9 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 GRB to ORD?
The 5am–8am departure window is the strongest at 81.7% on time. The 5pm–8pm window is the weakest at 52.0%, 30 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 GRB to ORD?
December is the weakest month at 60.3% on time, compared with 80.3% in September. Across the year that is 20 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 GRB — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on-time record75.6%
- Envoy Air on-time record75.1%
- SkyWest Airlines on-time record66.0%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. GRB to ORD and ORD to GRB 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.