Route reliability record
SMF→ORD
Sacramento to Chicago
- Flights
- 1,347
- Period
- September 2025 to August 2026
- Distance
- 1,781 mi
- Carriers
- 2
This route lands a B, 2 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 an hour and a half on average. That rests on 1,347 SMF to ORD flights, with a median arrival 6 minutes early.
Best time to fly SMF to ORD: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 86.7% of the time and Saturday flights 84.8%, against 79.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.3%
Arrivals under 15 minutes late, of 1,316 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
1.48%
National rate is 1.89%
Best carrier
United
81.2% on time across 990 flights
These figures cover 1,347 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
Which airline is most reliable on SMF to ORD
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 | 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
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 20 points, against half a point between the best and worst carrier.
- 5am–8am325 flights86.7%
- 8am–11am260 flights84.4%
- 11am–2pm81 flights77.5%
- 2pm–5pm374 flights66.9%
- 5pm–8pm—
- 8pm–5am307 flights83.1%
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 66.9% for the afternoon window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 374 flights scheduled in it.
Explore
Filter SMF to ORD 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 SMF to ORD, the best departure window is 5am–8am at 86.7% on time and the worst is 2pm–5pm at 66.9%, a wide gap of 19.8 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.7%
- 8–11am84.4%
- 11am–2pm77.5%
- 2–5pm66.9%
- 5–8pm—
- 8pm–5am83.1%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 20 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.
August is the worst month at 71.0% on time, 20 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 152 flights.
Across the week, Saturday is the strongest day at 84.8% on time and Sunday the weakest at 72.2%, a spread of 13 points.
Delay causes
Why this route gets delayed
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 23,000 reported delay minutes.
- 36%National Airspace System
- 34%Late-arriving aircraft
- 29%Carrier
- 1%Extreme weather
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 8,204 minutes out of 23,000, against a national NAS share of 21%. The split is drawn from 22,757 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 1.48% against a national 1.89%, which is ordinary. Diversions add another 0.82%.
Connections and stage length
What a delay here actually costs
7.2% 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 an hour and a half, 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 67.3% on time across 1,347 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.
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 ORD 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. February runs 91.1% on time and August 71.0%, a swing of 20 points. If the dates move at all, move them out of August before you think about anything else. 1,316 completed flights over 12 months sit behind that.
Common questions
SMF to ORD questions
How often is SMF to ORD delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.7% of the 1,347 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
How reliable is SMF to ORD compared with the rest of the country?
79.3% of flights arrive on time here against a national 77.3%, a difference of 2 points in its favour. That is worth a B on this site's grading scale.
What time of day has the fewest delays on SMF to ORD?
The 5am–8am departure window is the strongest at 86.7% on time. The 2pm–5pm window is the weakest at 66.9%, 20 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 August delays on SMF to ORD?
August is the weakest month at 71.0% on time, compared with 91.1% in February. Across the year that is 20 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
- ORD to SMF — the return legseparate record
- Sacramento International (SMF) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on SMF to ORD81.2%
- American Airlines on SMF to ORD74.0%
- SMF to LAX, a related route85.6%
- LGA to ORD, a related route66.7%
- SMF to SAN, a related route69.8%
- United Airlines on-time record81.2%
- American Airlines on-time record74.0%
- 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. SMF to ORD and ORD to SMF 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.