Route reliability record
GCC→DEN
Gillette to Denver
- Flights
- 747
- Period
- September 2025 to August 2026
- Distance
- 313 mi
- Carriers
- 1
This route lands a B+, 4 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by close to two hours on average. That rests on 747 GCC to DEN flights, with a median arrival 7 minutes early.
Best time to fly GCC to DEN: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 86.1% of the time and Wednesday flights 89.2%, against 81.5% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.3%. That gap is worth roughly 42 fewer late arrivals for every thousand flights.
Key figures
On time
81.5%
Arrivals under 15 minutes late, of 740 completed flights
Avg delay
106 min
Across delayed arrivals only, not all flights
Cancelled
0.80%
National rate is 1.89%
Best carrier
SkyWest
81.5% on time across 747 flights
These figures cover 747 flights between September 2025 and August 2026. The median arrival is 7 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
Which airline is most reliable on GCC to DEN
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 747 | 81.5% | 106 min | 0.80% | B+ |
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
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 25 points, against half a point between the best and worst carrier.
- 5am–8am310 flights86.1%
- 8am–11am72 flights84.7%
- 11am–2pm184 flights74.6%
- 2pm–5pm134 flights85.0%
- 5pm–8pm47 flights61.4%
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 61.4% on time, against 86.1% for the 5am–8am 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 5am–8am window is the busiest, with 310 flights scheduled in it.
Explore
Filter GCC to DEN by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On GCC to DEN, the best departure window is 5am–8am at 86.1% on time and the worst is 5pm–8pm at 61.4%, a wide gap of 24.7 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.1%
- 8–11am84.7%
- 11am–2pm74.6%
- 2–5pm85.0%
- 5–8pm61.4%
- 8pm–5am—
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 28 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 63.4% on time, 28 points below September, the best at 91.7%. 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 89 flights.
Across the week, Wednesday is the strongest day at 89.2% on time and Sunday the weakest at 73.2%, a spread of 16 points.
Delay causes
Why this route gets delayed
Carrier accounts for 63% of the 15,000 delay minutes carriers reported here, and the remaining four split what is left.
- 63%Carrier
- 17%National Airspace System
- 14%Late-arriving aircraft
- 6%Extreme weather
The largest share of delay minutes, 63%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 9,150 of the 15,000 delay minutes reported here. The split is drawn from 14,522 reported delay minutes.
Cancellations are rare at 0.80%, below the national 1.89% 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
7.4% 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 close to two hours, which a normal layover absorbs.
At 313 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 5am–8am window matters as much as it does.
The return leg runs 79.8% on time across 747 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. 747 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.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 747 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 81.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 740 completed flights over 12 months sit behind that.
Common questions
GCC to DEN questions
How often is GCC to DEN delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.5% of the 747 flights in this analysis, against 22.7% nationally. Delayed flights are late by close to two hours on average.
How reliable is GCC to DEN compared with the rest of the country?
81.5% of flights arrive on time here against a national 77.3%, a difference of 4 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on GCC to DEN?
The 5am–8am departure window is the strongest at 86.1% on time. The 5pm–8pm window is the weakest at 61.4%, 25 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 August delays on GCC to DEN?
August is the weakest month at 63.4% on time, compared with 91.7% in September. Across the year that is 28 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
- DEN to GCC — the return legseparate record
- Denver International (DEN) delay statistics
- PHX to DEN, a related route76.7%
- SLC to DEN, a related route79.0%
- LAX to DEN, a related route81.6%
- SkyWest Airlines on-time record81.5%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. GCC to DEN and DEN to GCC 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.