Carrier route record
UASMF→ORD
United Airlines · Sacramento to Chicago
- Flights
- 990
- Period
- September 2025 to August 2026
- Share of route
- 73%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SMF to ORD lands a B, 4 points better than the national rate of 77.3%. 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 rests on 990 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on SMF 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
81.2%
Arrivals under 15 minutes late, of 970 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.31%
National rate is 1.89%
Whole route
79.3%
Every carrier on SMF to ORD, 1,347 flights
These figures cover 990 flights between September 2025 and August 2026. The median arrival is 6 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.
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Carrier by carrier
United against every carrier on SMF to ORD
United flew 990 of the 1,347 flights on SMF to ORD, most of the route. Its 81.2% on time is 2 points better than the route as a whole, which runs 79.3%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 81.2% to American at 74.0%. 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) | 990 | 81.2% | 73 min | 1.31% | B |
| American Airlinesthin sample | 357 | 74.0% | 106 min | 1.96% | C |
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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 19 points, against half a point between the best and worst carrier.
- 5am–8am325 flights86.7%
- 8am–11am260 flights84.4%
- 11am–2pm2 flights—
- 2pm–5pm225 flights68.0%
- 5pm–8pm—
- 8pm–5am178 flights84.3%
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.7% of the time, against 68.0% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 325 flights scheduled in it.
Across the year
United on SMF to ORD through the year
July is the worst month at 69.8% on time, 21 points below February, the best at 91.1%. 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 93 flights.
Across the week, Thursday is the strongest day at 87.0% on time and Sunday the weakest at 74.1%, a spread of 13 points.
Arrival by arrival
How late United on SMF to ORD runs when it is late
United on SMF to ORD often beats the schedule: 291 of 970 completed flights, 30%, arrived 15 minutes or more early. The 182 late arrivals split 77 under half an hour, 43 between 30 and 60 minutes, and 62 an hour or more.
- 15+ min early291 flights30.0%
- Within 15 min497 flights51.2%
- 15–29 min late77 flights7.9%
- 30–59 min late43 flights4.4%
- 1–2 hours late32 flights3.3%
- 2+ hours late30 flights3.1%
Scale runs 0% to 100%.
Share of 970 completed flights by arrival against schedule.
35 of 139 late departures made up the time and arrived on time, 25% of them. In the other direction, 78 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 ORD.
The worst days
Worst days for United on SMF to ORD
The latest arrival of the period was on 24 June 2026, 13 hours 50 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 June 2026 | 13 hours 50 minutes | Late-arriving aircraft |
| 14 July 2026 | 6 hours 30 minutes | Late-arriving aircraft |
| 2 February 2026 | 6 hours 5 minutes | Carrier |
| 29 November 2025 | 5 hours 49 minutes | National Airspace System |
| 12 April 2026 | 5 hours 38 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
National Airspace System accounts for 51% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 51%National Airspace System
- 32%Late-arriving aircraft
- 15%Carrier
- 1%Extreme weather
51% 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 6,787 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 13,192 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 86.7% on time here.
Cancellations sit at 1.31% against a national 1.89%, which is ordinary. Diversions add another 0.71%.
Connections and stage length
What a delay here costs
6.4% of arrivals land an hour or more late, close to the national 8.3%, so 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 1,781 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 69.4% on time across 991 flights, 12 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 12 points of difference.
One caution: this is a thin sample. 990 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 SMF to ORD
Put together: treat all of this as provisional. 990 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 81.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 970 completed flights over 12 months sit behind that.
Related
Where to go next
- SMF to ORD, every carrier
- United on ORD to SMF, the return leg
- American Airlines on SMF to ORD74.0%
- United Airlines network-wide record
- Sacramento International (SMF) 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 7.05 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.