Route reliability record
DEN→HLN
Denver to Helena
- Flights
- 783
- Period
- September 2025 to August 2026
- Distance
- 594 mi
- Carriers
- 1
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 783 DEN to HLN flights, with a median arrival 5 minutes early.
Best time to fly DEN to HLN: a 2pm–5pm departure, ideally on a Sunday. Flights in that window arrived on time 85.5% of the time and Sunday flights 85.6%, against 80.9% for the route overall.
The US average over the same twelve months is 77.3%, 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
80.9%
Arrivals under 15 minutes late, of 776 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.51%
National rate is 1.89%
Best carrier
SkyWest
80.9% on time across 783 flights
These figures cover 783 flights between September 2025 and August 2026. The median arrival is 5 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.
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
Which airline is most reliable on DEN to HLN
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 | 783 | 80.9% | 70 min | 0.51% | B+ |
Flight by flight
Flights on DEN to HLN
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.
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 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 783 flights.
- 5am–8am—
- 8am–11am—
- 11am–2pm365 flights83.4%
- 2pm–5pm55 flights85.5%
- 5pm–8pm355 flights77.5%
- 8pm–5am8 flights—
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 2pm–5pm slot at 85.5% on time, ahead of 5pm–8pm at 77.5%. 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 11am–2pm window is the busiest, with 365 flights scheduled in it.
Explore
Filter DEN to HLN 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 DEN to HLN, the best departure window is 2pm–5pm at 85.5% on time and the worst is 5pm–8pm at 77.5%, a real gap of 8.0 points. All US flights leaving 2pm–5pm ran 71.9%.
- 5–8am—
- 8–11am—
- 11am–2pm83.4%
- 2–5pm85.5%
- 5–8pm77.5%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 32 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.
June is the worst month at 63.3% on time, 32 points below April, the best at 95.0%. 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. September was the busiest month here, with 90 flights.
Across the week, Sunday is the strongest day at 85.6% on time and Friday the weakest at 73.9%, a spread of 12 points.
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 10,000 reported delay minutes.
- 37%Carrier
- 27%National Airspace System
- 24%Late-arriving aircraft
- 12%Extreme weather
- 0%Security
Extreme weather accounts for 12% 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 2.0 times the usual weather exposure. The split is drawn from 10,420 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,827 of the 10,000 delay minutes reported here.
Cancellations are rare at 0.51%, 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
7.0% 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 a little over an hour, which a normal layover absorbs.
The 594 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 84.0% on time across 783 flights, 3 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 3 points of difference.
One caution: this is a thin sample. 783 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 HLN after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 783 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 80.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 776 completed flights over 12 months sit behind that.
Common questions
DEN to HLN questions
How often is DEN to HLN delayed?
About 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 19.1% of the 783 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is DEN to HLN compared with the rest of the country?
80.9% 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 DEN to HLN?
The 2pm–5pm departure window is the strongest at 85.5% on time. The 5pm–8pm window is the weakest at 77.5%, 8 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 June delays on DEN to HLN?
June is the weakest month at 63.3% on time, compared with 95.0% in April. Across the year that is 32 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
- HLN to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- DEN to PHX, a related route75.6%
- SLC to HLN, a related route95.2%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record80.9%
- 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. DEN to HLN and HLN to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed DEN to HLN’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.