Route reliability record
BOI→ORD
Boise to Chicago
- Flights
- 1,111
- Period
- September 2025 to August 2026
- Distance
- 1,437 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, 2 points worse than the national rate of 77.3%. The late ones land an hour and a half behind schedule. That rests on 1,111 BOI to ORD flights, with a median arrival 5 minutes early.
Best time to fly BOI to ORD: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 85.3% of the time and Tuesday flights 80.9%, against 74.9% for the route overall.
The US average over the same twelve months is 77.3%, 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
74.9%
Arrivals under 15 minutes late, of 1,092 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
1.17%
National rate is 1.89%
Best carrier
SkyWest
82.9% on time across 507 flights
These figures cover 1,111 flights between September 2025 and August 2026. Beyond the headline rate, 10.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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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 | 82.9% | 78 min | 2.17% | B |
| United Airlinesthin sample | 244 | 75.5% | 91 min | 0.82% | B+ |
| Envoy Airthin sample | 152 | 63.8% | 111 min | 0.00% | D+ |
| American Airlinesthin sample | 208 | 63.5% | 102 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.
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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.
- 5am–8am42 flights76.3%
- 8am–11am343 flights85.3%
- 11am–2pm575 flights71.4%
- 2pm–5pm151 flights64.9%
- 5pm–8pm—
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 85.3% of the time, against 64.9% 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 575 flights scheduled in it.
Explore
Filter BOI to ORD by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On BOI to ORD, the best departure window is 8am–11am at 85.3% on time and the worst is 2pm–5pm at 64.9%, a wide gap of 20.4 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am76.3%
- 8–11am85.3%
- 11am–2pm71.4%
- 2–5pm64.9%
- 5–8pm—
- 8pm–5am—
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
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.
August is the worst month at 65.6% on time, 25 points below February, the best at 90.5%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. December was the busiest month here, with 104 flights.
Across the week, Tuesday is the strongest day at 80.9% on time and Friday the weakest at 67.1%, a spread of 14 points.
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 26,000 reported delay minutes.
- 31%Late-arriving aircraft
- 27%Carrier
- 27%National Airspace System
- 15%Extreme weather
Extreme weather accounts for 15% 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 25,717 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 85.3% on time here.
Cancellations sit at 1.17% against a national 1.89%, which is ordinary. Diversions add another 0.54%.
Connections and stage length
What a delay here actually costs
10.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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.
The return leg is a different operation and performs like one: it runs 69.3% 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 August 65.6%, a swing of 25 points. If the dates move at all, move them out of August before you think about anything else. 1,092 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 25.1% of the 1,111 flights in this analysis, against 22.7% 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?
74.9% of flights arrive on time here against a national 77.3%, a difference of 2 points against it. That is worth a C 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 85.3% on time. The 2pm–5pm window is the weakest at 64.9%, 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 August delays on BOI to ORD?
August 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 ORD82.9%
- United Airlines on BOI to ORD75.5%
- Envoy Air on BOI to ORD63.8%
- American Airlines on BOI to ORD63.5%
- BOI to SEA, a related route84.9%
- LGA to ORD, a related route66.7%
- BOI to DEN, a related route81.7%
- SkyWest Airlines on-time record82.9%
- United Airlines on-time record75.5%
- Envoy Air on-time record63.8%
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
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.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.