Carrier route record
ASSAN→BOI
Alaska Airlines · San Diego to Boise
- Flights
- 253
- Period
- September 2025 to August 2026
- Share of route
- 24%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SAN to BOI lands a B, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That rests on 253 flights, with a median arrival 13 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Alaska on SAN to BOI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.2%
Arrivals under 15 minutes late, of 250 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
1.19%
National rate is 1.89%
Whole route
78.8%
Every carrier on SAN to BOI, 1,035 flights
These figures cover 253 flights between September 2025 and August 2026. The median arrival is 13 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.
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Carrier by carrier
Alaska against every carrier on SAN to BOI
Alaska flew 253 of the 1,035 flights on SAN to BOI, about 24% of it. Its 81.2% on time is 2 points better than the route as a whole, which runs 78.8%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 83.9% to Southwest at 73.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 Airlinesthin sample | 356 | 83.9% | 72 min | 0.28% | B+ |
| Alaska Airlines (this page)thin sample | 253 | 81.2% | 45 min | 1.19% | B |
| Southwest Airlines | 426 | 73.0% | 55 min | 0.00% | C+ |
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Departure window
When Alaska runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 253 flights.
The overnight block holds up unusually well at 80.5% on time across 224 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 224 flights scheduled in it.
Across the year
Alaska on SAN to BOI through the year
- Jul–Sep 202530 flights—
- Oct–Dec 202591 flights77.5%
- Jan–Mar 202690 flights80.0%
- Apr–Jun 202642 flights90.5%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 81.2% on time across 253 flights.
Alaska on SAN to BOI did not run the same all year. Its best quarter was Apr–Jun 2026 at 90.5% on time and its weakest Oct–Dec 2025 at 77.5%, a swing of 13 points on roughly 84 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Monday is the strongest day at 94.6% on time and Friday the weakest at 65.7%, a spread of 29 points.
Arrival by arrival
How late Alaska on SAN to BOI runs when it is late
Alaska on SAN to BOI often beats the schedule: 115 of 250 completed flights, 46%, arrived 15 minutes or more early. The 47 late arrivals split 19 under half an hour, 17 between 30 and 60 minutes, and 11 an hour or more.
- 15+ min early115 flights46.0%
- Within 15 min88 flights35.2%
- 15–29 min late19 flights7.6%
- 30–59 min late17 flights6.8%
- 1–2 hours late9 flights3.6%
- 2+ hours late2 flights0.8%
Scale runs 0% to 100%.
Share of 250 completed flights by arrival against schedule.
12 of 46 late departures made up the time and arrived on time, 26% of them. In the other direction, 13 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BOI.
The worst days
Worst days for Alaska on SAN to BOI
The latest arrival of the period was on 25 October 2025, 2 hours behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 25 October 2025 | 2 hours | Carrier |
| 14 December 2025 | 2 hours | Late-arriving aircraft |
| 20 December 2025 | 1 hour 54 minutes | Late-arriving aircraft |
| 28 March 2026 | 1 hour 40 minutes | Late-arriving aircraft |
| 23 March 2026 | 1 hour 39 minutes | Late-arriving aircraft |
Delay causes
Why Alaska runs late on this route
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 2,135 reported delay minutes.
- 41%Late-arriving aircraft
- 30%Carrier
- 22%National Airspace System
- 6%Extreme weather
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 2,135 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 2,135 reported delay minutes.
Cancellations sit at 1.19% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 4.4% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 749 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 90.0% on time across 252 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 253 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Alaska on SAN to BOI
Put together: treat all of this as provisional. 253 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 81.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 250 completed flights over 12 months sit behind that.
Related
Where to go next
- SAN to BOI, every carrier
- Alaska on BOI to SAN, the return leg
- SkyWest Airlines on SAN to BOI83.9%
- Southwest Airlines on SAN to BOI73.0%
- Alaska Airlines network-wide record
- San Diego International (SAN) delay statistics
- Why the first flight of the morning is statistically safest
- How to read this site: grades, sample sizes, and honest caveats
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.