Route reliability record
DEN→RKS
Denver to Rock Springs
- Flights
- 728
- Period
- July 2025 to June 2026
- Distance
- 260 mi
- Carriers
- 1
This route lands a B+, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 728 DEN to RKS flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.9%
Arrivals under 15 minutes late, of 715 completed flights
Avg delay
93 min
Across delayed arrivals only, not all flights
Cancelled
0.69%
National rate is 1.81%
Best carrier
SkyWest
77.9% on time across 728 flights
These figures cover 728 flights between July 2025 and June 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.
Carrier by carrier
Which airline is most reliable on DEN to RKS
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 | 728 | 77.9% | 93 min | 0.69% | B+ |
Flight by flight
Flights on DEN to RKS
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Departure window
The best time of day to leave
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 728 flights.
- 5am–8am—
- 8am–11am—
- 11am–2pm363 flights80.8%
- 2pm–5pm1 flights—
- 5pm–8pm—
- 8pm–5am364 flights74.9%
Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 80.8% on time, ahead of 8pm–5am at 74.9%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8pm–5am window is the busiest, with 364 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 36 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.
July is the worst month at 60.3% on time, 36 points below November, the best at 96.6%. 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. January was the busiest month here, with 62 flights.
Across the week, Wednesday is the strongest day at 86.3% on time and Friday the weakest at 69.2%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 43% of the 15,000 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.
- 43%Carrier
- 34%Late-arriving aircraft
- 17%National Airspace System
- 5%Extreme weather
34% 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 15,000 reported delay minutes here, that single category outweighs weather by 6 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 14,683 reported delay minutes.
The largest share of delay minutes, 43%, 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 6,364 of the 15,000 delay minutes reported here.
Cancellations are rare at 0.69%, 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 actually costs
7.7% 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 an hour and a half, which a normal layover absorbs.
At 260 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 11am–2pm window matters as much as it does.
The return leg is a different operation and performs like one: it runs 82.0% on time across 728 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 728 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 RKS after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 728 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 77.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 715 completed flights over 12 months sit behind that.
Common questions
DEN to RKS questions
How often is DEN to RKS 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 22.1% of the 728 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is DEN to RKS compared with the rest of the country?
77.9% of flights arrive on time here against a national 77.6%, a difference of half a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DEN to RKS?
The 11am–2pm departure window is the strongest at 80.8% on time. The 8pm–5am window is the weakest at 74.9%, 6 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 July delays on DEN to RKS?
July is the weakest month at 60.3% on time, compared with 96.6% in November. Across the year that is 36 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
- RKS to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- DEN to PHX, a related route75.7%
- DEN to SLC, a related route77.5%
- DEN to LAX, a related route79.0%
- SkyWest Airlines on-time record77.9%
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
Direction matters. DEN to RKS and RKS to DEN 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.