Route reliability record
BOI→PDX
Boise to Portland
- Flights
- 1,115
- Period
- July 2025 to June 2026
- Distance
- 344 mi
- Carriers
- 2
This route 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 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,115 BOI to PDX flights, of which SkyWest Airlines flew 457 at 92.3% on time.
Best time to fly BOI to PDX: a 8pm–5am departure, ideally on a Tuesday. Flights in that window arrived on time 100.0% of the time and Tuesday flights 96.1%, against 91.9% for the route overall.
Set against the rest of the country, this route's record is 14 points better than the US average of 77.6%. That gap is worth roughly 143 fewer late arrivals for every thousand flights.
Key figures
On time
91.9%
Arrivals under 15 minutes late, of 1,109 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.54%
National rate is 1.81%
Best carrier
SkyWest
92.3% on time across 457 flights
These figures cover 1,115 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
Which airline is most reliable on BOI to PDX
The two carriers here are closely matched: half a point 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 457 | 92.3% | 63 min | 1.09% | A |
| Alaska Airlines | 658 | 91.6% | 56 min | 0.15% | A+ |
No carrier stands out. SkyWest tops the table at 92.3%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Best ways to make this trip
The most reliable ways to fly Boise to Portland
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BOI → PDXBoise to Portland | Alaska Airlines | 91.5% | 91.6% | 0.15% | 5am–8am, Tue | — |
| 2. BOI → PDXBoise to Portland | SkyWest Airlines | 91.3% | 92.3% | 1.09% | 8am–11am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 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–8am285 flights95.8%
- 8am–11am216 flights94.9%
- 11am–2pm243 flights89.5%
- 2pm–5pm330 flights87.3%
- 5pm–8pm—
- 8pm–5am41 flights100.0%
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is the strongest at 100.0% on time. The full set of windows spans 13 points.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 1,115 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
December is the weak month at 84.8% on time, against 96.6% in October. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. September was the busiest month here, with 120 flights.
Across the week, Tuesday is the strongest day at 96.1% on time and Friday the weakest at 86.8%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 57% of the 5,308 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.
- 57%Late-arriving aircraft
- 31%Carrier
- 9%National Airspace System
- 3%Extreme weather
57% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 5,308 reported delay minutes here, that single category outweighs weather by 20 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 5,308 reported delay minutes.
Cancellations are rare at 0.54%, 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 actually costs
Badly late arrivals are rare here: only 2.3% 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 344 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 8pm–5am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 86.7% on time across 908 flights, 5 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 5 points of difference.
The sample behind these figures is 1,115 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.
Work out the risk of missing a connection in PDX after this flight
What to do with this
Booking this route
Put together: this route's record is 91.9% on time with 0.54% cancelled, worth an A+. The largest single lever is the 8pm–5am departure window, and the numbers below the table are where the reasoning behind that lives. 1,109 completed flights over 12 months sit behind that.
Common questions
BOI to PDX questions
How often is BOI to PDX delayed?
About one flight in twelve arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 8.1% of the 1,115 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on BOI to PDX?
SkyWest Airlines leads at 92.3% on time across 457 flights. Alaska Airlines is at the other end on 91.6%, a gap of half a point. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on BOI to PDX?
The 8pm–5am departure window is the strongest at 100.0% on time. The 2pm–5pm window is the weakest at 87.3%, 13 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on BOI to PDX?
December is the weakest month at 84.8% on time, compared with 96.6% in October. Across the year that is 12 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- PDX to BOI — the return legseparate record
- Portland International (PDX) delay statistics
- SkyWest Airlines on BOI to PDX92.3%
- Alaska Airlines on BOI to PDX91.6%
- BOI to SEA, a related route85.7%
- SEA to PDX, a related route83.1%
- BOI to DEN, a related route80.9%
- SkyWest Airlines on-time record92.3%
- Alaska Airlines on-time record91.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. BOI to PDX and PDX to BOI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.