Route reliability record
SMF→SFO
Sacramento to San Francisco
- Flights
- 1,360
- Period
- September 2025 to August 2026
- Distance
- 86 mi
- Carriers
- 2
This route draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 1,360 SMF to SFO flights, with a median arrival 3 minutes late.
Best time to fly SMF to SFO: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 90.2% of the time and Saturday flights 74.3%, against 62.2% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 15 points behind the country as a whole. Across a thousand flights that is about 151 extra late arrivals.
Key figures
On time
62.2%
Arrivals under 15 minutes late, of 1,337 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
1.69%
National rate is 1.89%
Best carrier
SkyWest
59.3% on time across 1,245 flights
These figures cover 1,360 flights between September 2025 and August 2026. Beyond the headline rate, 11.5% 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 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 | 115 | 93.0% | 65 min | 0.00% | A+ |
| SkyWest Airlines | 1,245 | 59.3% | 72 min | 1.85% | 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.
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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 63 points, against half a point between the best and worst carrier.
- 5am–8am387 flights90.2%
- 8am–11am119 flights40.2%
- 11am–2pm250 flights60.3%
- 2pm–5pm260 flights58.1%
- 5pm–8pm96 flights27.7%
- 8pm–5am248 flights47.5%
Scale runs 20% to 95%.
The 5pm–8pm window is where this operation falls apart: 27.7% on time, against 90.2% 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.
Explore
Filter SMF to SFO 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 SFO, the best departure window is 5am–8am at 90.2% on time and the worst is 5pm–8pm at 27.7%, a wide gap of 62.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am90.2%
- 8–11am40.2%
- 11am–2pm60.3%
- 2–5pm58.1%
- 5–8pm27.7%
- 8pm–5am47.5%
best all US flightsScale 20% to 95%.
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 74.3% on time and Friday the weakest at 52.8%, a spread of 22 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 44% of the 36,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 25%Late-arriving aircraft
- 25%Carrier
- 6%Extreme weather
44% 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 16,000 minutes out of 36,000, against a national NAS share of 21%. The split is drawn from 36,100 reported delay minutes.
Cancellations sit at 1.69% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
11.5% 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 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 76.0% on time across 1,359 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 1,360 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. 1,337 completed flights over 12 months sit behind that.
Common questions
SMF to SFO questions
How often is SMF to SFO delayed?
Roughly 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 37.8% of the 1,360 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is SMF to SFO compared with the rest of the country?
62.2% of flights arrive on time here against a national 77.3%, a difference of 15 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 90.2% on time. The 5pm–8pm window is the weakest at 27.7%, 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
- United Airlines on SMF to SFO93.0%
- SkyWest Airlines on SMF to SFO59.3%
- SMF to LAX, a related route85.6%
- LAX to SFO, a related route60.1%
- SMF to SAN, a related route69.8%
- United Airlines on-time record93.0%
- SkyWest Airlines on-time record59.3%
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.