75% of flights from San Francisco to Boise arrived on time over the past 12 months. That is worse than the typical U.S. route. The 8 a.m. departures ran on time 92% of the time; the 8 p.m. ones 63%. Most reliable airline: United Airlines (75%). 9% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SFO → BOI: when a flight was late, it was under 45 minutes late 51% of the time. About 1 in 11 flights landed an hour or more late, and 1 in 52 three hours or more; 0.3% were cancelled outright.
- On time or early75%
- 15–30 min late7.8%
- 30–60 min late8.1%
- 1–2 hours late5.2%
- 2–3 hours late1.6%
- 3+ hours late1.9%
- Diverted0.1%
- Cancelled0.3%
Share of all 1,823 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| United Airlines | 1,464 | 75% | 0.3% | −7 min | 8.3% | +71 min | SkyWest 84%, United Airlines 16% |
| Alaska Airlines | 359 | 74% | 0.3% | −7 min | 10.6% | +74 min | SkyWest 77%, Horizon Air 23% |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at SFO). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines | Alaska Airlines |
|---|---|---|
| 8 a.m. | 93% | — |
| 1 p.m. | 72% | — |
| 4 p.m. | 75% | — |
| 6 p.m. | 79% | — |
| 7 p.m. | — | 75% |
| 8 p.m. | 63% | — |
Last flight of the day
On SFO → BOI, each airline's last flight of the day was cancelled 0.5% of the time, against 0.3% for its earlier flights (2.0× as often). It arrived 3+ hours late 1.9% of the time (earlier flights: 1.9%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| United Airlines | 8:59 p.m. | 0.5% | 1.9% | 0.3% | first flight 10:15 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in BOI tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: March (85%). Worst: December (71%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 275 | 67% | 0.7% |
| Tuesday | 250 | 82% | 0.0% |
| Wednesday | 256 | 77% | 0.0% |
| Thursday | 265 | 70% | 0.0% |
| Friday | 271 | 71% | 0.4% |
| Saturday | 241 | 84% | 0.4% |
| Sunday | 265 | 75% | 0.8% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 3 · air traffic/airport 2 · airline 1
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| UA 5644 | 6:25 p.m. | 233 | 79% | 0.4% | −12 min | SkyWest |
| AS 3375 | 7:25 p.m. | 275 | 75% | 0.0% | −10 min | SkyWest |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| May 18, 2026 | 6 | 0% | 0 |
| Oct 1, 2025 | 5 | 0% | 0 |
| Jun 1, 2026 | 5 | 0% | 0 |
| Nov 21, 2025 | 5 | 0% | 0 |
| Dec 25, 2025 | 4 | 0% | 0 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of San Francisco or Boise. OAK → BOI has been 8 points more reliable.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| SFO → BOI (this route) | 1,823 | 75% | 0.3% |
| OAK → BOI Oakland to Boise /Gowen | 530 | 83% | 0.0% |
| SJC → BOI San Jose to Boise /Gowen | 689 | 82% | 0.3% |
Questions
How often are flights from SFO to BOI on time?
75% of 1,823 scheduled flights from San Francisco, CA to Boise, ID arrived within 15 minutes of schedule between September 2025 and August 2026. 0.3% were cancelled.
What is the best time of day to fly SFO to BOI?
Flights scheduled to leave at 8 a.m. were the most reliable (92% on time). The 8 p.m. departures were the least (63%).
Which airline is most on time from SFO to BOI?
United Airlines: 75% of its 1,464 flights on the route arrived on time. Alaska Airlines: 74%.
What month has the most delays from SFO to BOI?
December (71% on time). The best month is March (85%), over 2023–2026.
Is the last flight of the day from SFO to BOI more likely to be cancelled?
Yes. Each airline's last SFO–BOI flight of the day was cancelled 0.5% of the time over the past year, against 0.3% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- BOI → SFO (return)
- San Francisco (SFO) delays by hour
- Flights into Boise /Gowen (BOI)
- United Airlines on-time record
- Alaska Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.