Carrier route record
UAORD→SMF
United Airlines · Chicago to Sacramento
- Flights
- 991
- Period
- September 2025 to August 2026
- Share of route
- 74%
- Carriers
- 2
Historical statistics for September 2025 to August 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, 8 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 991 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so United on ORD to SMF runs 8 points behind the country as a whole. Across a thousand flights that is about 79 extra late arrivals.
Key figures
On time
69.4%
Arrivals under 15 minutes late, of 977 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
1.41%
National rate is 1.89%
Whole route
67.3%
Every carrier on ORD to SMF, 1,347 flights
These figures cover 991 flights between September 2025 and August 2026. Beyond the headline rate, 10.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
United against every carrier on ORD to SMF
United flew 991 of the 1,347 flights on ORD to SMF, most of the route. Its 69.4% on time is 2 points better than the route as a whole, which runs 67.3%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 69.4% to American at 61.6%. 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) | 991 | 69.4% | 65 min | 1.41% | C |
| American Airlinesthin sample | 356 | 61.6% | 62 min | 2.25% | D |
Flight by flight
United flight numbers on ORD to SMF
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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 22 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am365 flights82.2%
- 11am–2pm—
- 2pm–5pm315 flights62.7%
- 5pm–8pm49 flights62.5%
- 8pm–5am262 flights60.5%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 60.5% on time, against 82.2% 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, Monday is the strongest day at 75.4% on time and Friday the weakest at 64.3%, a spread of 11 points.
Arrival by arrival
How late United on ORD to SMF runs when it is late
The 299 late arrivals split 110 under half an hour, 83 between 30 and 60 minutes, and 106 an hour or more.
- 15+ min early232 flights23.7%
- Within 15 min446 flights45.6%
- 15–29 min late110 flights11.3%
- 30–59 min late83 flights8.5%
- 1–2 hours late64 flights6.6%
- 2+ hours late42 flights4.3%
Scale runs 0% to 100%.
Share of 977 completed flights by arrival against schedule.
46 of 259 late departures made up the time and arrived on time, 18% of them. In the other direction, 86 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SMF.
The worst days
Worst days for United on ORD to SMF
The latest arrival of the period was on 24 June 2026, 13 hours 20 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 June 2026 | 13 hours 20 minutes | Late-arriving aircraft |
| 3 July 2026 | 6 hours 2 minutes | Late-arriving aircraft |
| 30 January 2026 | 5 hours 42 minutes | Late-arriving aircraft |
| 30 November 2025 | 4 hours 41 minutes | Late-arriving aircraft |
| 25 January 2026 | 4 hours 20 minutes | Extreme weather |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 49% of the 19,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Late-arriving aircraft
- 28%Carrier
- 17%National Airspace System
- 5%Extreme weather
49% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 19,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 19,348 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 82.2% on time here.
Cancellations sit at 1.41% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
10.8% 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 1,781 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 81.2% on time across 990 flights, 12 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 12 points of difference.
One caution: this is a thin sample. 991 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. 991 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 69.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 977 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 SMF61.6%
- 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 7.05 million flight records
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.