Route reliability record
SMF→SFO
Sacramento to San Francisco
- Flights
- 1,378
- Period
- July 2025 to June 2026
- Distance
- 86 mi
- Carriers
- 2
This route draws a D. 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 1,378 SMF to SFO flights, with a median arrival right on schedule.
Best time to fly SMF to SFO: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 89.9% of the time and Saturday flights 75.6%, against 64.6% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 13 points behind the country as a whole. Across a thousand flights that is about 130 extra late arrivals.
Key figures
On time
64.6%
Arrivals under 15 minutes late, of 1,354 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.74%
National rate is 1.81%
Best carrier
SkyWest
63.5% on time across 1,325 flights
These figures cover 1,378 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on SMF to SFO
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 Airlinesthin sample | 53 | 92.5% | 54 min | 0.00% | A+ |
| SkyWest Airlines | 1,325 | 63.5% | 68 min | 1.81% | D |
Flight by flight
Flights on SMF to SFO
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.
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 63 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–8am387 flights89.9%
- 8am–11am181 flights53.4%
- 11am–2pm185 flights60.4%
- 2pm–5pm289 flights64.5%
- 5pm–8pm50 flights27.1%
- 8pm–5am286 flights45.8%
Scale runs 20% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 27.1% on time, against 89.9% for the 5am–8am 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 5am–8am window is the busiest, with 387 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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 51.1% on time, 27 points below March, the best at 78.1%. 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. October was the busiest month here, with 145 flights.
Across the week, Saturday is the strongest day at 75.6% on time and Monday the weakest at 56.3%. 19 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 32,000 reported delay minutes.
- 41%National Airspace System
- 27%Carrier
- 25%Late-arriving aircraft
- 7%Extreme weather
41% 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 13,000 minutes out of 32,000, against a national NAS share of 21%. The split is drawn from 32,441 reported delay minutes.
Cancellations sit at 1.74% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.6% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 86 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 78.9% on time across 1,377 flights, 14 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 14 points of difference.
The sample behind these figures is 1,378 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 SFO 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. March runs 78.1% on time and June 51.1%, a swing of 27 points. If the dates move at all, move them out of June before you think about anything else. 1,354 completed flights over 12 months sit behind that.
Common questions
SMF to SFO questions
How often is SMF to SFO 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 35.4% of the 1,378 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is SMF to SFO compared with the rest of the country?
64.6% of flights arrive on time here against a national 77.6%, a difference of 13 points against it. That is worth a D on this site's grading scale.
What time of day has the fewest delays on SMF to SFO?
The 5am–8am departure window is the strongest at 89.9% on time. The 5pm–8pm window is the weakest at 27.1%, 63 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 SMF to SFO?
June is the weakest month at 51.1% on time, compared with 78.1% in March. Across the year that is 27 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
- SFO to SMF — the return legseparate record
- Sacramento International (SMF) delay statistics
- San Francisco International (SFO) delay statistics
- SMF to LAX, a related route86.0%
- LAX to SFO, a related route64.8%
- SMF to SAN, a related route73.3%
- United Airlines on-time record92.5%
- SkyWest Airlines on-time record63.5%
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.04 million flight records
Direction matters. SMF to SFO and SFO 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.