Route reliability record
IDA→DEN
Idaho Falls to Denver
- Flights
- 1,738
- Period
- July 2025 to June 2026
- Distance
- 458 mi
- Carriers
- 3
This route lands a B+, 2 points better than the national rate of 77.6%. About 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 1,738 IDA to DEN flights, with a median arrival 11 minutes early.
Best time to fly IDA to DEN: a 8am–11am departure, ideally on a Sunday. Flights in that window arrived on time 88.4% of the time and Sunday flights 83.3%, against 79.2% for the route overall.
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
79.2%
Arrivals under 15 minutes late, of 1,714 completed flights
Avg delay
91 min
Across delayed arrivals only, not all flights
Cancelled
0.75%
National rate is 1.81%
Best carrier
SkyWest
79.4% on time across 1,536 flights
These figures cover 1,738 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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 IDA 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 |
|---|---|---|---|---|---|
| United Airlinesthin sample | 184 | 80.3% | 103 min | 0.00% | B+ |
| SkyWest Airlines | 1,536 | 79.4% | 91 min | 0.78% | B+ |
| Allegiant Airthin sample | 18 | 50.0% | 64 min | 5.56% | F− |
Flight by flight
Flights on IDA to DEN
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 matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am518 flights87.8%
- 8am–11am289 flights88.4%
- 11am–2pm89 flights87.6%
- 2pm–5pm588 flights70.3%
- 5pm–8pm252 flights68.7%
- 8pm–5am2 flights—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 88.4% of the time, against 68.7% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 588 flights scheduled in it.
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.
July is the worst month at 58.4% on time, 32 points below November, the best at 90.8%. 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. July was the busiest month here, with 192 flights.
Across the week, Sunday is the strongest day at 83.3% on time and Saturday the weakest at 76.7%. 7 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 45% of the 32,000 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.
- 45%Carrier
- 26%National Airspace System
- 21%Late-arriving aircraft
- 8%Extreme weather
The largest share of delay minutes, 45%, 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 14,000 of the 32,000 delay minutes reported here. The split is drawn from 32,449 reported delay minutes.
Cancellations are rare at 0.75%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.7% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 458 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 8am–11am window matters as much as it does.
The return leg runs 80.3% on time across 1,737 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 1,738 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.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 90.8% on time and July 58.4%, a swing of 32 points. If the dates move at all, move them out of July before you think about anything else. 1,714 completed flights over 12 months sit behind that.
Common questions
IDA to DEN questions
How often is IDA to DEN 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 20.8% of the 1,738 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is IDA to DEN compared with the rest of the country?
79.2% of flights arrive on time here against a national 77.6%, a difference of 2 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on IDA to DEN?
The 8am–11am departure window is the strongest at 88.4% on time. The 5pm–8pm window is the weakest at 68.7%, 20 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 IDA to DEN?
July is the weakest month at 58.4% on time, compared with 90.8% in November. 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
- DEN to IDA — the return legseparate record
- Denver International (DEN) delay statistics
- United Airlines on IDA to DEN80.3%
- SkyWest Airlines on IDA to DEN79.4%
- IDA to SLC, a related route91.6%
- PHX to DEN, a related route77.2%
- SLC to DEN, a related route77.8%
- United Airlines on-time record80.3%
- SkyWest Airlines on-time record79.4%
- Allegiant Air on-time record50.0%
- The best time of day to fly, according to 7.04 million flight records
- How often a connection fails at the major US hubs
Direction matters. IDA to DEN and DEN to IDA 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.