Carrier route record
OOSEA→BOI
SkyWest Airlines · Seattle to Boise
- Flights
- 3,081
- Period
- July 2025 to June 2026
- Share of route
- 78%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with SkyWest Airlines.
SkyWest on SEA to BOI 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 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs roughly 50 minutes. That rests on 3,081 flights, with a median arrival 9 minutes early.
Set against the rest of the country, SkyWest's SEA to BOI record is 10 points better than the US average of 77.6%. That gap is worth roughly 96 fewer late arrivals for every thousand flights.
Key figures
On time
87.2%
Arrivals under 15 minutes late, of 3,074 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.19%
National rate is 1.81%
Whole route
85.8%
Every carrier on SEA to BOI, 3,972 flights
These figures cover 3,081 flights between July 2025 and June 2026. The median arrival is 9 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 SEA to BOI
SkyWest flew 3,081 of the 3,972 flights on SEA to BOI, most of the route. Its 87.2% on time is about level with the route as a whole at 85.8%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from SkyWest at 87.2% to Alaska at 80.8%.
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 (this page) | 3,081 | 87.2% | 52 min | 0.19% | A+ |
| Alaska Airlines | 891 | 80.8% | 43 min | 0.45% | B+ |
Flight by flight
SkyWest flight numbers on SEA to BOI
Departure window
When SkyWest 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 3,081 flights.
- 5am–8am394 flights92.4%
- 8am–11am597 flights88.3%
- 11am–2pm495 flights87.3%
- 2pm–5pm516 flights85.2%
- 5pm–8pm709 flights85.8%
- 8pm–5am370 flights85.1%
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
The early departures do better, though not dramatically: 92.4% on time for the 5am–8am window against 85.1% for 8pm–5am. Worth taking if the schedule allows, not worth an extra connection. The 5pm–8pm window is the busiest, with 709 flights scheduled in it.
Across the year
SkyWest on SEA to BOI through the year
July is the worst month at 82.6% on time, 10 points below October, the best at 92.6%. 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 333 flights.
Across the week, Saturday is the strongest day at 91.0% on time and Sunday the weakest at 84.3%. 7 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 53% of the 20,000 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.
- 53%Carrier
- 20%Extreme weather
- 14%National Airspace System
- 12%Late-arriving aircraft
- 0%Security
Extreme weather accounts for 20% 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 3.3 times the usual weather exposure. The split is drawn from 20,408 reported delay minutes.
The largest share of delay minutes, 53%, 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 11,000 of the 20,000 delay minutes reported here.
Cancellations are rare at 0.19%, 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 3.6% 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 86.2% on time across 2,929 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 3,081 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 SEA to BOI
Put together: take the 5am–8am departure, avoid July if the dates are flexible, and if two carriers are within a few dollars of each other, Alaska is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 7 points, which is the most any booking decision can do. 3,074 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to BOI, every carrier
- SkyWest on BOI to SEA, the return leg
- Alaska Airlines on SEA to BOI80.8%
- SkyWest Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Worst months to fly in the US, ranked by the data
- Late aircraft, weather, or the airline: what actually causes US flight delays
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.