Route reliability record
ORD→SFO
Chicago to San Francisco
- Flights
- 72,535
- Period
- June 2025 to May 2026
- Distance
- 1,842 mi
- Carriers
- 3
This route sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 75.9%. The late ones land about an hour behind schedule. That rests on 72,535 flights, of which Republic Airways flew 21,317 at 77.9% on time.
Republic Airways is the most reliable of the three carriers covered here at 77.9% on time across 21,317 flights.
Key figures
On time
69.9%
Arrivals under 15 minutes late, of 70,142 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
3.02%
National rate is 2.23%
Best carrier
Republic
77.9% on time across 21,317 flights
These figures cover 73,000 flights between June 2025 and May 2026. Beyond the headline rate, 10.4% 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 SFO
The choice of carrier is not cosmetic here. Republic Airways arrives on time 77.9% of the time; Frontier Airlines manages 65.3%. Sample sizes sit next to every figure, because a two-point gap across 26,874 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 21,317 | 77.9% | 56 min | 3.34% | B− |
| PSA Airlines | 24,344 | 68.1% | 65 min | 3.66% | C− |
| Frontier Airlines | 26,874 | 65.3% | 60 min | 2.18% | C |
PSA Airlines cancels 3.7% 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 18 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am11,242 flights79.5%
- 8am–11am14,870 flights74.5%
- 11am–2pm13,420 flights70.5%
- 2pm–5pm12,693 flights66.0%
- 5pm–8pm13,056 flights61.5%
- 8pm–5am7,253 flights68.0%
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 79.5% 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.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 72,535 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
January is the weak month at 62.9% on time, against 73.9% in May. 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.
Across the week, Saturday is the strongest day at 74.2% on time and Friday the weakest at 66.8%. 7 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 50% of the 1.29 million 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.
- 50%Late-arriving aircraft
- 24%National Airspace System
- 21%Carrier
- 5%Extreme weather
- 0%Security
50% 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 1.29 million reported delay minutes here, that single category outweighs weather by 9 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.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 79.5% on time here.
Cancellations run at 3.02%, against 2.23% nationally. That is roughly one flight in 30 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. 10.4% of arrivals land a full hour or more behind schedule, against 8.6% 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 1,842 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
72,535 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.02% cancellation rate. A late arrival costs you about an hour; 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.
Common questions
ORD to SFO questions
How often is ORD to SFO 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 30.1% of the 72,535 flights in this analysis, against 24.1% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ORD to SFO?
Republic Airways leads at 77.9% on time across 21,317 flights. Frontier Airlines is at the other end on 65.3%, 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 SFO?
The 5am–8am departure window is the strongest at 79.5% on time. The 5pm–8pm window is the weakest at 61.5%, 18 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 January delays on ORD to SFO?
January is the weakest month at 62.9% on time, compared with 73.9% in May. Across the year that is 11 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
- Chicago O'Hare International (ORD) delay statistics
- San Francisco International (SFO) delay statistics
- Republic Airways on-time record77.9%
- PSA Airlines on-time record68.1%
- Frontier Airlines on-time record65.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 11.3 million flight records
The reverse direction, SFO to ORD, does not clear this site’s 365-flight floor and has no page of its own.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.