Route reliability record
SMF→ORD
Sacramento to Chicago
- Flights
- 1,324
- Period
- July 2025 to June 2026
- Distance
- 1,781 mi
- Carriers
- 2
This route lands a B, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,324 SMF to ORD flights, with a median arrival 5 minutes early.
Best time to fly SMF to ORD: a 5am–8am departure, ideally on a Thursday. Flights in that window arrived on time 88.6% of the time and Thursday flights 81.5%, against 76.9% for the route overall.
The US average over the same twelve months is 77.6%, 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
76.9%
Arrivals under 15 minutes late, of 1,297 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
1.06%
National rate is 1.81%
Best carrier
United
79.5% on time across 987 flights
These figures cover 1,324 flights between July 2025 and June 2026. The median arrival is 5 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.
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 | 987 | 79.5% | 69 min | 1.01% | B |
| American Airlinesthin sample | 337 | 69.1% | 97 min | 1.19% | C |
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 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–8am325 flights88.6%
- 8am–11am254 flights85.2%
- 11am–2pm85 flights77.4%
- 2pm–5pm372 flights60.7%
- 5pm–8pm—
- 8pm–5am288 flights77.1%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 88.6% of the time, against 60.7% for the afternoon window. That is 28 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 372 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 39 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.
July is the worst month at 51.7% on time, 39 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, Thursday is the strongest day at 81.5% on time and Sunday the weakest at 71.9%. 10 points is a smaller lever than departure hour, but it is free.
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.
- 37%Late-arriving aircraft
- 33%National Airspace System
- 28%Carrier
- 1%Extreme weather
37% 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 23,000 reported delay minutes here, that single category outweighs weather by 25 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 23,495 reported delay minutes.
33% 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 7,807 minutes out of 23,000, against a national NAS share of 21%.
Cancellations sit at 1.06% against a national 1.81%, which is ordinary. Diversions add another 0.98%.
Connections and stage length
What a delay here actually costs
7.8% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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 66.2% on time across 1,324 flights, 11 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 11 points of difference.
The sample behind these figures is 1,324 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 July 51.7%, a swing of 39 points. If the dates move at all, move them out of July before you think about anything else. 1,297 completed flights over 12 months sit behind that.
Common questions
SMF to ORD questions
How often is SMF to ORD delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.1% of the 1,324 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is SMF to ORD compared with the rest of the country?
76.9% of flights arrive on time here against a national 77.6%, a difference of half a point against it. 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 88.6% on time. The 2pm–5pm window is the weakest at 60.7%, 28 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 July delays on SMF to ORD?
July is the weakest month at 51.7% on time, compared with 91.1% in February. Across the year that is 39 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 ORD79.5%
- American Airlines on SMF to ORD69.1%
- SMF to LAX, a related route86.0%
- LGA to ORD, a related route67.3%
- SMF to SAN, a related route73.3%
- United Airlines on-time record79.5%
- American Airlines on-time record69.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.