Route reliability record
BOI→ORD
Boise to Chicago
- Flights
- 1,111
- Period
- July 2025 to June 2026
- Distance
- 1,437 mi
- Carriers
- 4
This route sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,111 BOI to ORD flights, with a median arrival 4 minutes early.
Best time to fly BOI to ORD: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 86.4% of the time and Saturday flights 81.7%, against 75.3% 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
75.3%
Arrivals under 15 minutes late, of 1,093 completed flights
Avg delay
86 min
Across delayed arrivals only, not all flights
Cancelled
0.99%
National rate is 1.81%
Best carrier
SkyWest
83.6% on time across 507 flights
These figures cover 1,111 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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 BOI to ORD
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 507 | 83.6% | 75 min | 1.78% | B |
| United Airlinesthin sample | 244 | 77.1% | 85 min | 0.82% | B+ |
| Envoy Airthin sample | 188 | 63.8% | 99 min | 0.00% | D+ |
| American Airlinesthin sample | 172 | 61.4% | 88 min | 0.00% | D+ |
Flight by flight
Flights on BOI to ORD
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 20 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–8am42 flights76.3%
- 8am–11am343 flights86.4%
- 11am–2pm637 flights70.6%
- 2pm–5pm89 flights66.3%
- 5pm–8pm—
- 8pm–5am—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 86.4% of the time, against 66.3% for the afternoon window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 637 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 25 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.
Delays peak in April, when the on-time rate falls to 65.6%. February is the strongest month at 90.5%. Moving a flexible trip across that boundary buys 25 points. December was the busiest month here, with 104 flights.
Across the week, Saturday is the strongest day at 81.7% on time and Friday the weakest at 65.6%. 16 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 23,000 reported delay minutes.
- 34%Late-arriving aircraft
- 26%Carrier
- 24%National Airspace System
- 16%Extreme weather
Extreme weather accounts for 16% 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 2.5 times the usual weather exposure. The split is drawn from 23,236 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.4% on time here.
Cancellations sit at 0.99% against a national 1.81%, which is ordinary. Diversions add another 0.63%.
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. 9.7% 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 1,437 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 69.1% on time across 1,108 flights, 6 points below 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 6 points of difference.
The sample behind these figures is 1,111 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 ORD 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. February runs 90.5% on time and April 65.6%, a swing of 25 points. If the dates move at all, move them out of April before you think about anything else. 1,093 completed flights over 12 months sit behind that.
Common questions
BOI to ORD questions
How often is BOI to ORD delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.7% of the 1,111 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is BOI to ORD compared with the rest of the country?
75.3% of flights arrive on time here against a national 77.6%, a difference of 2 points against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on BOI to ORD?
The 8am–11am departure window is the strongest at 86.4% on time. The 2pm–5pm window is the weakest at 66.3%, 20 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 April delays on BOI to ORD?
April is the weakest month at 65.6% on time, compared with 90.5% in February. Across the year that is 25 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 BOI — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- SkyWest Airlines on BOI to ORD83.6%
- United Airlines on BOI to ORD77.1%
- Envoy Air on BOI to ORD63.8%
- American Airlines on BOI to ORD61.4%
- BOI to SEA, a related route85.7%
- LGA to ORD, a related route67.3%
- BOI to DEN, a related route80.9%
- SkyWest Airlines on-time record83.6%
- United Airlines on-time record77.1%
- Envoy Air on-time record63.8%
- 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. BOI to ORD and ORD to BOI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed BOI to ORD’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.