Route reliability record
SFO→ORD
San Francisco to Chicago
- Flights
- 5,650
- Period
- September 2025 to August 2026
- Distance
- 1,846 mi
- Carriers
- 2
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 77.3%. The late ones land an hour and a half behind schedule. That rests on 5,650 SFO to ORD flights, of which United Airlines flew 3,885 at 76.6% on time.
Best time to fly SFO to ORD: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 92.3% of the time and Tuesday flights 81.2%, against 75.0% 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
75.0%
Arrivals under 15 minutes late, of 5,554 completed flights
Avg delay
85 min
Across delayed arrivals only, not all flights
Cancelled
0.96%
National rate is 1.89%
Best carrier
United
76.6% on time across 3,885 flights
These figures cover 5,650 flights between September 2025 and August 2026. Beyond the headline rate, 9.6% 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 SFO to ORD
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 3,885 | 76.6% | 70 min | 0.67% | B+ |
| American Airlines | 1,765 | 71.6% | 113 min | 1.59% | C |
No carrier stands out. United tops the table at 76.6%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on SFO 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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Best ways to make this trip
The most reliable ways to fly San Francisco to Chicago
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SFO → ORDSan Francisco to Chicago | United Airlines | 76.1% | 76.6% | 0.67% | 5am–8am, Tue | UA 2091 06:00 |
| 2. SFO → ORDSan Francisco to Chicago | American Airlines | 70.5% | 71.6% | 1.59% | 5am–8am, Sat | AA 2614 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 35 points, against 5 points between the best and worst carrier.
- 5am–8am1,048 flights92.3%
- 8am–11am1,130 flights76.9%
- 11am–2pm678 flights57.7%
- 2pm–5pm1,040 flights60.3%
- 5pm–8pm542 flights74.3%
- 8pm–5am1,212 flights80.9%
Scale runs 50% to 100%.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 57.7% on time against 92.3% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8pm–5am window is the busiest, with 1,212 flights scheduled in it.
Explore
Filter SFO 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 SFO to ORD, the best departure window is 5am–8am at 92.3% on time and the worst is 11am–2pm at 57.7%, a wide gap of 34.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.3%
- 8–11am76.9%
- 11am–2pm57.7%
- 2–5pm60.3%
- 5–8pm74.3%
- 8pm–5am80.9%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 19 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.
July is the worst month at 65.8% on time, 19 points below February, the best at 85.2%. 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. May was the busiest month here, with 559 flights.
Across the week, Tuesday is the strongest day at 81.2% on time and Monday the weakest at 70.5%, a spread of 11 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 118,000 reported delay minutes.
- 39%Late-arriving aircraft
- 32%Carrier
- 26%National Airspace System
- 2%Extreme weather
- 0%Security
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 118,000 reported delay minutes here, that single category outweighs weather by 17 to one. The split is drawn from 118,379 reported delay minutes.
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 92.3% on time here.
Cancellations sit at 0.96% against a national 1.89%, which is ordinary. Diversions add another 0.74%.
Connections and stage length
What a delay here actually costs
9.6% 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.
At 1,846 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.
The return leg is a different operation and performs like one: it runs 66.2% on time across 5,649 flights, 9 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 9 points of difference.
The sample behind these figures is 5,650 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 85.2% on time and July 65.8%, a swing of 19 points. If the dates move at all, move them out of July before you think about anything else. 5,554 completed flights over 12 months sit behind that.
Common questions
SFO to ORD questions
How often is SFO 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 25.0% of the 5,650 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on SFO to ORD?
United Airlines leads at 76.6% on time across 3,885 flights. American Airlines is at the other end on 71.6%, a gap of 5 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 SFO to ORD?
The 5am–8am departure window is the strongest at 92.3% on time. The 11am–2pm window is the weakest at 57.7%, 35 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 July delays on SFO to ORD?
July is the weakest month at 65.8% on time, compared with 85.2% in February. Across the year that is 19 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 SFO — the return legseparate record
- San Francisco International (SFO) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on SFO to ORD76.6%
- American Airlines on SFO to ORD71.6%
- SFO to LAX, a related route70.9%
- LGA to ORD, a related route66.7%
- SFO to SEA, a related route72.3%
- United Airlines on-time record76.6%
- American Airlines on-time record71.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SFO to ORD and ORD to SFO 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.