Route reliability record
BOI→SFO
Boise to San Francisco
- Flights
- 1,744
- Period
- September 2025 to August 2026
- Distance
- 522 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 a little over an hour behind schedule. Build slack into anything you connect to. That rests on 1,744 BOI to SFO flights, with a median arrival right on schedule.
Best time to fly BOI to SFO: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 92.8% of the time and Saturday flights 77.1%, against 65.3% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 12 points behind the country as a whole. Across a thousand flights that is about 120 extra late arrivals.
Key figures
On time
65.3%
Arrivals under 15 minutes late, of 1,728 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
0.40%
National rate is 1.89%
Best carrier
SkyWest
66.0% on time across 1,513 flights
These figures cover 1,744 flights between September 2025 and August 2026. Beyond the headline rate, 14.4% 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 BOI 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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 1,513 | 66.0% | 71 min | 0.40% | C+ |
| United Airlinesthin sample | 231 | 61.3% | 104 min | 0.43% | D+ |
Flight by flight
Flights on BOI 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 44 points, against half a point between the best and worst carrier.
- 5am–8am379 flights92.8%
- 8am–11am527 flights56.6%
- 11am–2pm229 flights49.1%
- 2pm–5pm268 flights68.6%
- 5pm–8pm341 flights56.5%
- 8pm–5am—
Scale runs 40% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 49.1% on time against 92.8% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 527 flights scheduled in it.
Explore
Filter BOI 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 BOI to SFO, the best departure window is 5am–8am at 92.8% on time and the worst is 11am–2pm at 49.1%, a wide gap of 43.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.8%
- 8–11am56.6%
- 11am–2pm49.1%
- 2–5pm68.6%
- 5–8pm56.5%
- 8pm–5am—
best all US flightsScale 40% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 41 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 40.5% on time, 41 points below March, the best at 81.5%. 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. March was the busiest month here, with 178 flights.
Across the week, Saturday is the strongest day at 77.1% on time and Monday the weakest at 59.6%, a spread of 17 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 54% of the 46,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%National Airspace System
- 28%Carrier
- 17%Late-arriving aircraft
- 2%Extreme weather
54% 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 24,000 minutes out of 46,000, against a national NAS share of 21%. The split is drawn from 45,628 reported delay minutes.
Cancellations are rare at 0.40%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
14.4% 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.
The 522 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 75.4% on time across 1,740 flights, 10 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 10 points of difference.
The sample behind these figures is 1,744 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 81.5% on time and June 40.5%, a swing of 41 points. If the dates move at all, move them out of June before you think about anything else. 1,728 completed flights over 12 months sit behind that.
Common questions
BOI to SFO questions
How often is BOI 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 34.7% of the 1,744 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is BOI to SFO compared with the rest of the country?
65.3% of flights arrive on time here against a national 77.3%, a difference of 12 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on BOI to SFO?
The 5am–8am departure window is the strongest at 92.8% on time. The 11am–2pm window is the weakest at 49.1%, 44 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 BOI to SFO?
June is the weakest month at 40.5% on time, compared with 81.5% in March. Across the year that is 41 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 BOI — the return legseparate record
- San Francisco International (SFO) delay statistics
- SkyWest Airlines on BOI to SFO66.0%
- United Airlines on BOI to SFO61.3%
- BOI to SEA, a related route84.9%
- LAX to SFO, a related route60.1%
- BOI to DEN, a related route81.7%
- SkyWest Airlines on-time record66.0%
- United Airlines on-time record61.3%
- 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. BOI to SFO and SFO to BOI 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.