Carrier route record
UASFO→ORD
United Airlines · San Francisco to Chicago
- Flights
- 3,815
- Period
- July 2025 to June 2026
- Share of route
- 68%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on SFO to ORD lands a B, level with the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 3,815 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate United on SFO to ORD from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.3%
Arrivals under 15 minutes late, of 3,756 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
1.02%
National rate is 1.81%
Whole route
76.5%
Every carrier on SFO to ORD, 5,628 flights
These figures cover 3,815 flights between July 2025 and June 2026. The median arrival is 7 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
United against every carrier on SFO to ORD
United flew 3,815 of the 5,628 flights on SFO to ORD, most of the route. Its 78.3% on time is 2 points better than the route as a whole, which runs 76.5%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 78.3% to Alaska at 52.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 |
|---|---|---|---|---|---|
| United Airlines (this page) | 3,815 | 78.3% | 71 min | 1.02% | B |
| American Airlines | 1,763 | 73.2% | 111 min | 1.76% | C |
| Alaska Airlinesthin sample | 50 | 52.2% | 49 min | 6.00% | F− |
Flight by flight
United flight numbers on SFO to ORD
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 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–8am706 flights92.1%
- 8am–11am730 flights78.7%
- 11am–2pm345 flights62.6%
- 2pm–5pm697 flights66.4%
- 5pm–8pm460 flights79.2%
- 8pm–5am877 flights81.9%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 62.6% on time against 92.1% 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 877 flights scheduled in it.
Across the year
United on SFO to ORD through the year
June is the worst month at 70.5% on time, 17 points below September, the best at 87.8%. 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 370 flights.
Across the week, Tuesday is the strongest day at 85.3% on time and Monday the weakest at 73.5%. 12 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
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 58,000 reported delay minutes.
- 40%Late-arriving aircraft
- 36%National Airspace System
- 24%Carrier
- 0%Extreme weather
40% 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 58,000 reported delay minutes here, that single category outweighs weather by 40 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 split is drawn from 57,517 reported delay minutes.
36% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 21,000 minutes out of 58,000, against a national NAS share of 21%.
Cancellations sit at 1.02% against a national 1.81%, which is ordinary. Diversions add another 0.52%.
Connections and stage length
What a delay here costs
7.7% 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 a little over an hour, which a normal layover absorbs.
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 69.8% on time across 3,813 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 3,815 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.
What to do with this
Booking United on SFO to ORD
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.8% on time and June 70.5%, a swing of 17 points. If the dates move at all, move them out of June before you think about anything else. 3,756 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to ORD, every carrier
- United on ORD to SFO, the return leg
- American Airlines on SFO to ORD73.2%
- United Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.