Carrier route record

F9CLE→DEN

Frontier Airlines · Cleveland to Denver

Flights: 296
Period: September 2025 to August 2026
Share of route: 16%
Carriers: 3

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

Frontier on CLE to DEN lands a B, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 296 flights. The strongest carrier on the route with a full sample, United Airlines, flew 940 at 87.5% on time.

The US average over the same twelve months is 77.3%, so there is little to separate Frontier on CLE to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

77.3%

Arrivals under 15 minutes late, of 291 completed flights

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

1.69%

National rate is 1.89%

Whole route

82.4%

Every carrier on CLE to DEN, 1,845 flights

These figures cover 296 flights between September 2025 and August 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.

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Carrier by carrier

Frontier against every carrier on CLE to DEN

Frontier flew 296 of the 1,845 flights on CLE to DEN, about 16% of it. Its 77.3% on time is 5 points worse than the route as a whole, which runs 82.4%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from United at 87.5% to Southwest at 76.9%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 87.5% of the time; Southwest Airlines manages 76.9%. Sample sizes sit next to every figure, because a two-point gap across 609 flights means less than a ten-point one.

On-time performance by carrier on CLE to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	940	87.5%	69 min	0.11%	A+
Frontier Airlines (this page)thin sample	296	77.3%	59 min	1.69%	B
Southwest Airlines	609	76.9%	60 min	0.66%	B+

United leads Southwest by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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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 32 points, against 11 points between the best and worst carrier.

5am–8am21 flights—
8am–11am1 flights—
11am–2pm147 flights90.3%
2pm–5pm21 flights—
5pm–8pm39 flights71.1%
8pm–5am67 flights58.5%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 58.5% on time, against 90.3% for the 11am–2pm slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 11am–2pm window is the busiest, with 147 flights scheduled in it.

Across the year

Frontier on CLE to DEN through the year

Jul–Sep 202521 flights—
Oct–Dec 202573 flights62.5%
Jan–Mar 202655 flights68.5%
Apr–Jun 202685 flights90.5%
Jul–Sep 202662 flights88.5%

Scale runs 55% to 95%. 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 77.3% on time across 296 flights.

Frontier on CLE to DEN did not run the same all year. Its best quarter was Apr–Jun 2026 at 90.5% on time and its weakest Oct–Dec 2025 at 62.5%, a swing of 28 points on roughly 74 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, Saturday is the strongest day at 86.5% on time and Tuesday the weakest at 71.4%, a spread of 15 points.

Arrival by arrival

How late Frontier on CLE to DEN runs when it is late

Frontier on CLE to DEN often beats the schedule: 115 of 291 completed flights, 40%, arrived 15 minutes or more early. The 66 late arrivals split 22 under half an hour, 23 between 30 and 60 minutes, and 21 an hour or more.

15+ min early115 flights39.5%
Within 15 min110 flights37.8%
15–29 min late22 flights7.6%
30–59 min late23 flights7.9%
1–2 hours late16 flights5.5%
2+ hours late5 flights1.7%

Scale runs 0% to 100%.

Share of 291 completed flights by arrival against schedule.

A late pushback is often recovered here: of 76 departures that left 15 minutes late or more, 25 still arrived on time. In the other direction, 15 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 DEN.

The worst days

Worst days for Frontier on CLE to DEN

The latest arrival of the period was on 8 September 2025, 4 hours 37 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.

The latest arrivals of Frontier on CLE to DEN in the period
Date	Arrived late by	Largest filed cause
8 September 2025	4 hours 37 minutes	Late-arriving aircraft
14 December 2025	4 hours 34 minutes	Late-arriving aircraft
16 February 2026	2 hours 58 minutes	Late-arriving aircraft
2 August 2026	2 hours 51 minutes	Late-arriving aircraft
17 March 2026	2 hours 21 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Late-arriving aircraft accounts for 52% of the 3,900 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
52%
National Airspace System
27%
Carrier
19%
Extreme weather
2%

52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,900 reported delay minutes here, that single category outweighs weather by 32 to one. The split is drawn from 3,900 reported delay minutes.

Cancellations sit at 1.69% against a national 1.89%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

7.2% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

The 1,201 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 is a different operation and performs like one: it runs 85.3% on time across 298 flights, 8 points above 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 8 points of difference.

One caution: this is a thin sample. 296 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 CLE to DEN

Put together: treat all of this as provisional. 296 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 77.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 291 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures