Route reliability record
ORD→SMF
Chicago to Sacramento
- Flights
- 1,347
- Period
- September 2025 to August 2026
- Distance
- 1,781 mi
- Carriers
- 2
This route draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,347 ORD to SMF flights, with a median arrival right on schedule.
Best time to fly ORD to SMF: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 82.8% of the time and Tuesday flights 72.8%, against 67.3% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 10 points behind the country as a whole. Across a thousand flights that is about 100 extra late arrivals.
Key figures
On time
67.3%
Arrivals under 15 minutes late, of 1,323 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
1.63%
National rate is 1.89%
Best carrier
United
69.4% on time across 991 flights
These figures cover 1,347 flights between September 2025 and August 2026. Beyond the headline rate, 11.9% 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 ORD to SMF
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 | 991 | 69.4% | 65 min | 1.41% | C |
| American Airlinesthin sample | 356 | 61.6% | 62 min | 2.25% | D |
Flight by flight
Flights on ORD to SMF
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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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 29 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am412 flights82.8%
- 11am–2pm180 flights67.8%
- 2pm–5pm315 flights62.7%
- 5pm–8pm71 flights53.6%
- 8pm–5am369 flights55.9%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 53.6% on time, against 82.8% 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 412 flights scheduled in it.
Explore
Filter ORD to SMF 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 ORD to SMF, the best departure window is 8am–11am at 82.8% on time and the worst is 5pm–8pm at 53.6%, a wide gap of 29.2 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am82.8%
- 11am–2pm67.8%
- 2–5pm62.7%
- 5–8pm53.6%
- 8pm–5am55.9%
best all US flightsScale 45% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 23 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.
June is the worst month at 56.4% on time, 23 points below September, the best at 79.5%. 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 151 flights.
Across the week, Tuesday is the strongest day at 72.8% on time and Friday the weakest at 62.4%, a spread of 10 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 49% of the 28,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Late-arriving aircraft
- 29%Carrier
- 17%National Airspace System
- 6%Extreme weather
49% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 28,000 reported delay minutes here, that single category outweighs weather by 8 to one. The split is drawn from 27,604 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 82.8% on time here.
Cancellations sit at 1.63% against a national 1.89%, which is ordinary. Diversions add another 0.15%.
Connections and stage length
What a delay here actually costs
11.9% 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 79.3% on time across 1,347 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.
The sample behind these figures is 1,347 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 SMF 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. September runs 79.5% on time and June 56.4%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 1,323 completed flights over 12 months sit behind that.
Common questions
ORD to SMF questions
How often is ORD to SMF delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 32.7% of the 1,347 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is ORD to SMF compared with the rest of the country?
67.3% of flights arrive on time here against a national 77.3%, a difference of 10 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on ORD to SMF?
The 8am–11am departure window is the strongest at 82.8% on time. The 5pm–8pm window is the weakest at 53.6%, 29 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 June delays on ORD to SMF?
June is the weakest month at 56.4% on time, compared with 79.5% in September. Across the year that is 23 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
- SMF to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Sacramento International (SMF) delay statistics
- United Airlines on ORD to SMF69.4%
- American Airlines on ORD to SMF61.6%
- ORD to LGA, a related route66.6%
- LAX to SMF, a related route84.8%
- ORD to BOS, a related route66.6%
- United Airlines on-time record69.4%
- American Airlines on-time record61.6%
- 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. ORD to SMF and SMF to ORD 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.