Carrier route record

ASBOI→SAN

Alaska Airlines · Boise to San Diego

Flights: 263
Period: July 2025 to June 2026
Share of route: 25%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.

Alaska on BOI to SAN earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 35 minutes. That rests on 263 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 404 at 82.2% on time.

Set against the rest of the country, Alaska's BOI to SAN record is 12 points better than the US average of 77.6%. That gap is worth roughly 116 fewer late arrivals for every thousand flights.

On time

89.2%

Arrivals under 15 minutes late, of 260 completed flights

Avg delay

34 min

Across delayed arrivals only, not all flights

Cancelled

1.14%

National rate is 1.81%

Whole route

82.1%

Every carrier on BOI to SAN, 1,039 flights

These figures cover 263 flights between July 2025 and June 2026. The median arrival is 7 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.

Carrier by carrier

Alaska against every carrier on BOI to SAN

Alaska flew 263 of the 1,039 flights on BOI to SAN, about 25% of it. Its 89.2% on time is 7 points better than the route as a whole, which runs 82.1%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from Alaska at 89.2% to Southwest at 77.0%.

The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on BOI to SAN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Alaska Airlines (this page)thin sample	263	89.2%	34 min	1.14%	A
SkyWest Airlines	404	82.2%	60 min	0.50%	B+
Southwest Airlines	372	77.0%	46 min	0.27%	B+

No carrier stands out. SkyWest tops the table at 82.2%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 263 flights.

There are not enough flights in each departure window to split Alaska's BOI to SAN record by time of day without the percentages moving on noise. The headline rate of 89.2% is the reliable figure here.

Across the year

Alaska on BOI to SAN through the year

Jul–Sep 202541 flights87.5%
Oct–Dec 202590 flights92.1%
Jan–Mar 202690 flights86.5%
Apr–Jun 202642 flights90.5%

Scale runs 80% to 100%. 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 89.2% on time across 263 flights.

Quarter by quarter Alaska on BOI to SAN held fairly steady: 87.5% in Jul–Sep 2025, 92.1% in Oct–Dec 2025, 86.5% in Jan–Mar 2026 and 90.5% in Apr–Jun 2026. A spread of 6 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Wednesday is the strongest day at 94.6% on time and Sunday the weakest at 81.1%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Alaska runs late on this route

One category carries most of the weight here. National Airspace System accounts for 65% of the 950 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

National Airspace System
65%
Carrier
33%
Extreme weather
1%

65% 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 622 minutes out of 950, against a national NAS share of 21%. The split is drawn from 950 reported delay minutes.

Cancellations sit at 1.14% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 1.5% land an hour or more behind schedule, against 8.1% 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 80.9% on time across 265 flights, 8 points below 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 8 points of difference.

One caution: this is a thin sample. 263 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 BOI to SAN

Put together: treat all of this as provisional. 263 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 89.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 260 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures