Skip to content
DelayAtlas

Carrier route record

F9SFO→SLC

Frontier Airlines · San Francisco to Salt Lake City

Flights
206
Period
September 2025 to August 2026
Share of route
6%
Carriers
4
CGRADE

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

Frontier on SFO to SLC draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 206 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,008 at 75.9% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 75.9% on time across 1,008 flights.

Key figures

On time

65.8%

Arrivals under 15 minutes late, of 202 completed flights

Avg delay

76 min

Across delayed arrivals only, not all flights

Cancelled

1.94%

National rate is 1.89%

Whole route

75.0%

Every carrier on SFO to SLC, 3,431 flights

These figures cover 206 flights between September 2025 and August 2026. Beyond the headline rate, 13.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Carrier by carrier

Frontier against every carrier on SFO to SLC

Frontier flew 206 of the 3,431 flights on SFO to SLC, about 6% of it. Its 65.8% on time is 9 points worse than the route as a whole, which runs 75.0%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 75.9% to Frontier at 65.8%.

The three carriers here are closely matched: about 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.

On-time performance by carrier on SFO to SLC
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlines1,00875.9%68 min1.39%B
Delta Air Lines1,71475.7%74 min0.93%B+
United Airlines50374.7%57 min0.20%C+
Frontier Airlines (this page)thin sample20665.8%76 min1.94%C

No carrier stands out. SkyWest tops the table at 75.9%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

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 20 points, against about a point between the best and worst carrier.

  • 5am–8am—
  • 8am–11am33 flights84.8%
  • 11am–2pm11 flights—
  • 2pm–5pm12 flights—
  • 5pm–8pm150 flights65.3%
  • 8pm–5am—

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 84.8% of the time, against 65.3% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 150 flights scheduled in it.

Across the year

Frontier on SFO to SLC through the year

  • Jul–Sep 202517 flights—
  • Oct–Dec 202537 flights58.3%
  • Jan–Mar 202633 flights81.8%
  • Apr–Jun 202663 flights71.0%
  • Jul–Sep 202656 flights48.1%

Scale runs 40% to 85%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 65.8% on time across 206 flights.

Frontier on SFO to SLC did not run the same all year. Its best quarter was Jan–Mar 2026 at 81.8% on time and its weakest Jul–Sep 2026 at 48.1%, a swing of 34 points on roughly 52 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Friday is the strongest day at 67.4% on time and Monday the weakest at 58.3%, a spread of 9 points.

Arrival by arrival

How late Frontier on SFO to SLC runs when it is late

Frontier on SFO to SLC often beats the schedule: 57 of 202 completed flights, 28%, arrived 15 minutes or more early. The 69 late arrivals split 14 under half an hour, 28 between 30 and 60 minutes, and 27 an hour or more.

  • 15+ min early57 flights28.2%
  • Within 15 min76 flights37.6%
  • 15–29 min late14 flights6.9%
  • 30–59 min late28 flights13.9%
  • 1–2 hours late17 flights8.4%
  • 2+ hours late10 flights5.0%

Scale runs 0% to 100%.

Share of 202 completed flights by arrival against schedule.

17 of 74 late departures made up the time and arrived on time, 23% of them. In the other direction, 12 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SLC.

The worst days

Worst days for Frontier on SFO to SLC

The latest arrival of the period was on 16 November 2025, 13 hours 49 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as a late-arriving aircraft.

The latest arrivals of Frontier on SFO to SLC in the period
DateArrived late byLargest filed cause
16 November 202513 hours 49 minutesCarrier
1 September 20255 hours 20 minutesLate-arriving aircraft
22 December 20252 hours 56 minutesLate-arriving aircraft
3 August 20262 hours 53 minutesLate-arriving aircraft
16 May 20262 hours 49 minutesLate-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 66% of the 5,225 delay minutes carriers reported here, and the remaining four split what is left.

  • Late-arriving aircraft
    66%
  • Carrier
    21%
  • National Airspace System
    12%
  • Extreme weather
    0%

66% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,225 reported delay minutes here, that single category outweighs weather by 66 to one. The split is drawn from 5,225 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 84.8% on time here.

Cancellations sit at 1.94% against a national 1.89%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

13.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.

The 599 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.

The return leg runs 65.2% on time across 206 flights, within half a point 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. 206 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 SFO to SLC

Put together: treat all of this as provisional. 206 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 65.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 202 completed flights over 12 months sit behind that.

Related

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.