Carrier route record

OOBOI→PHX

SkyWest Airlines · Boise to Phoenix

Flights: 1,000
Period: July 2025 to June 2026
Share of route: 50%
Carriers: 5

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

SkyWest on BOI to PHX 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 an hour and a half. That rests on 1,000 flights, with a median arrival 9 minutes early.

Set against the rest of the country, SkyWest's BOI to PHX record is 9 points better than the US average of 77.6%. That gap is worth roughly 89 fewer late arrivals for every thousand flights.

On time

86.5%

Arrivals under 15 minutes late, of 991 completed flights

Avg delay

95 min

Across delayed arrivals only, not all flights

Cancelled

0.60%

National rate is 1.81%

Whole route

83.9%

Every carrier on BOI to PHX, 1,985 flights

These figures cover 1,000 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 BOI to PHX

SkyWest flew 1,000 of the 1,985 flights on BOI to PHX, most of the route. Its 86.5% on time is 3 points better than the route as a whole, which runs 83.9%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from SkyWest at 86.5% to Alaska at 60.0%. Three 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.

On-time performance by carrier on BOI to PHX
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines (this page)	1,000	86.5%	95 min	0.60%	A+
Southwest Airlines	813	82.8%	60 min	0.49%	B+
Envoy Airthin sample	115	75.7%	45 min	0.00%	B+
American Airlinesthin sample	52	73.1%	103 min	0.00%	C+
Alaska Airlinesthin sample	5	60.0%	21 min	0.00%	D+

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 16 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–8am396 flights94.4%
8am–11am41 flights87.8%
11am–2pm144 flights83.8%
2pm–5pm154 flights81.5%
5pm–8pm265 flights78.6%
8pm–5am—

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 94.4% of the time, against 78.6% for the evening window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 396 flights scheduled in it.

Across the year

SkyWest on BOI to PHX through the year

Darker means more delays. Figures are on-time percentages.March best, January worst

January is the weak month at 77.9% on time, against 95.3% in March. 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. October was the busiest month here, with 114 flights.

Across the week, Saturday is the strongest day at 88.8% on time and Thursday the weakest at 84.2%. 5 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest 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 13,000 reported delay minutes.

Late-arriving aircraft
41%
Carrier
35%
National Airspace System
12%
Extreme weather
11%

Extreme weather accounts for 11% 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 1.8 times the usual weather exposure. The split is drawn from 12,765 reported delay minutes.

41% 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 13,000 reported delay minutes here, that single category outweighs weather by 4 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.

Cancellations are rare at 0.60%, 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 4.8% 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.

The 735 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 runs 84.0% on time across 1,001 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 1,000 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 SkyWest on BOI to PHX

Put together: treat all of this as provisional. 1,000 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 86.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 991 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