Carrier route record

F9PHX→SLC

Frontier Airlines · Phoenix to Salt Lake City

Flights: 677
Period: July 2025 to June 2026
Share of route: 12%
Carriers: 6

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

Frontier on PHX to SLC lands a B, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 677 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,708 at 90.4% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 90.4% on time across 1,708 flights.

On time

83.6%

Arrivals under 15 minutes late, of 663 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

1.77%

National rate is 1.81%

Whole route

83.0%

Every carrier on PHX to SLC, 5,757 flights

These figures cover 677 flights between July 2025 and June 2026. The median arrival is 11 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

Frontier against every carrier on PHX to SLC

Frontier flew 677 of the 5,757 flights on PHX to SLC, about 12% of it. Its 83.6% on time is about level with the route as a whole at 83.0%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from Delta at 90.4% to Southwest at 75.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 90.4% of the time; Southwest Airlines manages 75.5%. Sample sizes sit next to every figure, because a two-point gap across 1,858 flights means less than a ten-point one.

On-time performance by carrier on PHX to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,708	90.4%	75 min	0.59%	A+
American Airlinesthin sample	266	86.7%	70 min	0.38%	A+
Frontier Airlines (this page)	677	83.6%	78 min	1.77%	B
Envoy Airthin sample	89	83.1%	46 min	0.00%	B+
SkyWest Airlines	1,159	83.1%	67 min	0.26%	B+
Southwest Airlines	1,858	75.5%	48 min	0.32%	B+

The spread between Delta and Southwest is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.

Flight by flight

Frontier flight numbers on PHX to SLC

F9 144006:0090.5% · 256 flights

Departure window

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am118 flights87.2%
8am–11am175 flights90.8%
11am–2pm168 flights86.0%
2pm–5pm163 flights72.2%
5pm–8pm43 flights80.5%
8pm–5am10 flights—

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 90.8% of the time, against 72.2% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 175 flights scheduled in it.

Across the year

Frontier on PHX to SLC through the year

Darker means more delays. Figures are on-time percentages.November best, July worst

July is the worst month at 64.1% on time, 28 points below November, the best at 92.0%. 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. March was the busiest month here, with 73 flights.

Across the week, Tuesday is the strongest day at 95.8% on time and Sunday the weakest at 76.1%. 20 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Carrier accounts for 47% of the 8,456 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
47%
Late-arriving aircraft
43%
National Airspace System
9%
Extreme weather
1%

43% 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 8,456 reported delay minutes here, that single category outweighs weather by 39 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 8,456 reported delay minutes.

The largest share of delay minutes, 47%, 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 3,956 of the 8,456 delay minutes reported here.

Cancellations sit at 1.77% against a national 1.81%, which is ordinary. Diversions add another 0.30%.

Connections and stage length

What a delay here costs

5.6% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.

The 507 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 81.5% on time across 677 flights, within 2 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. 677 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 Frontier on PHX to SLC

Put together: treat all of this as provisional. 677 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 83.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 663 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