Carrier route record

OOBOI→SEA

SkyWest Airlines · Boise to Seattle

Flights: 2,929
Period: July 2025 to June 2026
Share of route: 77%
Carriers: 2

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

SkyWest on BOI to SEA earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 2,929 flights, with a median arrival 12 minutes early.

Set against the rest of the country, SkyWest's BOI to SEA record is 9 points better than the US average of 77.6%. That gap is worth roughly 86 fewer late arrivals for every thousand flights.

On time

86.2%

Arrivals under 15 minutes late, of 2,918 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

Whole route

85.7%

Every carrier on BOI to SEA, 3,820 flights

These figures cover 2,929 flights between July 2025 and June 2026. The median arrival is 12 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

SkyWest against every carrier on BOI to SEA

SkyWest flew 2,929 of the 3,820 flights on BOI to SEA, most of the route. Its 86.2% on time is about level with the route as a whole at 85.7%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from SkyWest at 86.2% to Alaska at 84.0%.

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.

On-time performance by carrier on BOI to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines (this page)	2,929	86.2%	58 min	0.27%	A+
Alaska Airlines	891	84.0%	50 min	0.79%	B+

Flight by flight

SkyWest flight numbers on BOI to SEA

Departure window

When SkyWest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 32 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am671 flights94.2%
8am–11am800 flights85.4%
11am–2pm382 flights87.9%
2pm–5pm596 flights83.3%
5pm–8pm365 flights83.5%
8pm–5am115 flights62.6%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.6% on time, against 94.2% 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 8am–11am window is the busiest, with 800 flights scheduled in it.

Across the year

SkyWest on BOI to SEA through the year

Darker means more delays. Figures are on-time percentages.February best, August worst

August is the worst month at 81.6% on time, 12 points below February, the best at 93.4%. 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. July was the busiest month here, with 301 flights.

Across the week, Saturday is the strongest day at 89.7% on time and Thursday the weakest at 81.9%. 8 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest runs late on this route

One category carries most of the weight here. Carrier accounts for 57% of the 23,000 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.

Carrier
57%
National Airspace System
17%
Extreme weather
17%
Late-arriving aircraft
9%
Security
0%

Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.7 times the usual weather exposure. The split is drawn from 23,408 reported delay minutes.

The largest share of delay minutes, 57%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 13,000 of the 23,000 delay minutes reported here.

Cancellations are rare at 0.27%, below the national 1.81% 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 costs

Badly late arrivals are rare here: only 3.8% 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.

At 399 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 runs 87.2% on time across 3,081 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 2,929 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.

What to do with this

Booking SkyWest on BOI to SEA

Put together: avoid the 8pm–5am departure. It runs 62.6% on time against 94.2% for the 5am–8am slot, and that 32 points is the largest single thing you control here. Alaska Airlines is the strongest operator if the fares are close. 2,918 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