Route reliability record
ORD→BHM
Chicago to Birmingham
- Flights
- 1,137
- Period
- July 2025 to June 2026
- Distance
- 584 mi
- Carriers
- 4
This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,137 ORD to BHM flights, with a median arrival 9 minutes early.
Best time to fly ORD to BHM: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 85.1% of the time and Tuesday flights 83.6%, against 78.5% 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
78.5%
Arrivals under 15 minutes late, of 1,117 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
1.76%
National rate is 1.81%
Best carrier
Envoy
79.3% on time across 773 flights
These figures cover 1,137 flights between July 2025 and June 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on ORD to BHM
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 |
|---|---|---|---|---|---|
| PSA Airlinesthin sample | 2 | 100.0% | — | 0.00% | A+ |
| Republic Airwaysthin sample | 255 | 82.8% | 59 min | 1.96% | B |
| Envoy Air | 773 | 79.3% | 64 min | 1.68% | B |
| SkyWest Airlinesthin sample | 107 | 61.9% | 70 min | 1.87% | D |
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 11 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–11am361 flights85.1%
- 11am–2pm46 flights76.1%
- 2pm–5pm374 flights76.3%
- 5pm–8pm16 flights—
- 8pm–5am340 flights74.0%
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 85.1% of the time, against 74.0% for the overnight window. That is 11 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 374 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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 64.4% on time, against 90.9% 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. February was the busiest month here, with 125 flights.
Across the week, Tuesday is the strongest day at 83.6% on time and Friday the weakest at 75.8%. 8 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 44% of the 15,000 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.
- 44%Late-arriving aircraft
- 22%Extreme weather
- 20%National Airspace System
- 14%Carrier
Extreme weather accounts for 22% 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 3.5 times the usual weather exposure. The split is drawn from 15,399 reported delay minutes.
44% 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 15,000 reported delay minutes here, that single category outweighs weather by 2 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 sit at 1.76% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
7.4% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 584 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 77.4% on time across 1,137 flights, within about 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 1,137 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.
Work out the risk of missing a connection in BHM after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.9% on time and December 64.4%, a swing of 27 points. If the dates move at all, move them out of December before you think about anything else. 1,117 completed flights over 12 months sit behind that.
Common questions
ORD to BHM questions
How often is ORD to BHM delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.5% of the 1,137 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is ORD to BHM compared with the rest of the country?
78.5% of flights arrive on time here against a national 77.6%, a difference of about a point in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on ORD to BHM?
The 8am–11am departure window is the strongest at 85.1% on time. The 8pm–5am window is the weakest at 74.0%, 11 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 BHM?
December is the weakest month at 64.4% on time, compared with 90.9% in September. Across the year that is 27 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
- BHM to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on ORD to BHM82.8%
- Envoy Air on ORD to BHM79.3%
- SkyWest Airlines on ORD to BHM61.9%
- ORD to LGA, a related route67.3%
- ATL to BHM, a related route84.0%
- ORD to BOS, a related route67.6%
- PSA Airlines on-time record100.0%
- Republic Airways on-time record82.8%
- Envoy Air on-time record79.3%
- 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 BHM and BHM 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.