Carrier route record
UAORD→SMF
United Airlines · Chicago to Sacramento
- Flights
- 988
- Period
- July 2025 to June 2026
- Share of route
- 75%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on ORD to SMF sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 988 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.6%, so United on ORD to SMF runs 9 points behind the country as a whole. Across a thousand flights that is about 93 extra late arrivals.
Key figures
On time
68.3%
Arrivals under 15 minutes late, of 978 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
1.01%
National rate is 1.81%
Whole route
66.2%
Every carrier on ORD to SMF, 1,324 flights
These figures cover 988 flights between July 2025 and June 2026. Beyond the headline rate, 11.2% 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
United against every carrier on ORD to SMF
United flew 988 of the 1,324 flights on ORD to SMF, most of the route. Its 68.3% on time is 2 points better than the route as a whole, which runs 66.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 68.3% to American at 59.9%. 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) | 988 | 68.3% | 67 min | 1.01% | C |
| American Airlinesthin sample | 336 | 59.9% | 60 min | 1.49% | D |
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 28 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–8am—
- 8am–11am365 flights82.5%
- 11am–2pm—
- 2pm–5pm315 flights64.1%
- 5pm–8pm49 flights62.5%
- 8pm–5am259 flights54.2%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 54.2% on time, against 82.5% for the 8am–11am 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. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Across the year
United on ORD to SMF through the year
December is the weak month at 57.3% on time, against 80.4% 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. May was the busiest month here, with 93 flights.
Across the week, Tuesday is the strongest day at 73.6% on time and Saturday the weakest at 62.2%. 11 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 21,000 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.
- 46%Late-arriving aircraft
- 30%Carrier
- 17%National Airspace System
- 8%Extreme weather
46% 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 21,000 reported delay minutes here, that single category outweighs weather by 6 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 20,741 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 82.5% on time here.
Cancellations sit at 1.01% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.2% 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.
At 1,781 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 79.5% on time across 987 flights, 11 points above 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 11 points of difference.
One caution: this is a thin sample. 988 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking United on ORD to SMF
Put together: treat all of this as provisional. 988 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 68.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 978 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to SMF, every carrier
- United on SMF to ORD, the return leg
- American Airlines on ORD to SMF59.9%
- United Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- Sacramento International (SMF) 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.