Route reliability record

RAP→DEN

Rapid City to Denver

Flights: 2,887
Period: July 2025 to June 2026
Distance: 301 mi
Carriers: 2

This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrive 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 2,887 flights, of which United Airlines flew 761 at 82.4% on time.

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.

On time

79.0%

Arrivals under 15 minutes late, of 2,842 completed flights

Avg delay

80 min

Across delayed arrivals only, not all flights

Cancelled

1.35%

National rate is 1.81%

Best carrier

United

82.4% on time across 761 flights

These figures cover 2,887 flights between July 2025 and June 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airline is most reliable on RAP to DEN

The two carriers here are closely matched: 5 points 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 RAP to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	761	82.4%	60 min	0.92%	B+
SkyWest Airlines	2,126	77.8%	85 min	1.51%	B

No carrier stands out. United tops the table at 82.4%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 17 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am723 flights85.8%
8am–11am611 flights77.8%
11am–2pm689 flights85.2%
2pm–5pm608 flights69.0%
5pm–8pm254 flights69.5%
8pm–5am2 flights—

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 85.8% of the time, against 69.0% for the afternoon window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 723 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 21 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.

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

July is the worst month at 65.3% on time, 21 points below February, the best at 86.5%. 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. August was the busiest month here, with 276 flights.

Across the week, Sunday is the strongest day at 84.3% on time and Friday the weakest at 73.3%. 11 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 47,000 reported delay minutes.

Carrier
40%
National Airspace System
23%
Late-arriving aircraft
23%
Extreme weather
14%

Extreme weather accounts for 14% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.3 times the usual weather exposure. The split is drawn from 47,470 reported delay minutes.

The largest share of delay minutes, 40%, 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 19,000 of the 47,000 delay minutes reported here.

Cancellations sit at 1.35% against a national 1.81%, which is ordinary. Diversions add another 0.21%.

Connections and stage length

What a delay here actually costs

8.1% 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 are the a little over an hour kind, which a normal layover absorbs.

At 301 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 77.9% on time across 2,887 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 2,887 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 86.5% on time and July 65.3%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 2,842 completed flights over 12 months sit behind that.

Common questions

RAP to DEN questions

How often is RAP to DEN delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.0% of the 2,887 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on RAP to DEN?

United Airlines leads at 82.4% on time across 761 flights. SkyWest Airlines is at the other end on 77.8%, a gap of 5 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on RAP to DEN?

The 5am–8am departure window is the strongest at 85.8% on time. The 2pm–5pm window is the weakest at 69.0%, 17 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 RAP to DEN?

July is the weakest month at 65.3% on time, compared with 86.5% in February. Across the year that is 21 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. RAP to DEN and DEN to RAP are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures