Route reliability record
IDA→SLC
Idaho Falls to Salt Lake City
- Flights
- 1,189
- Period
- July 2025 to June 2026
- Distance
- 189 mi
- Carriers
- 2
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 14 points better than the national rate of 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 1,189 IDA to SLC flights, with a median arrival 10 minutes early.
Best time to fly IDA to SLC: a 11am–2pm departure, ideally on a Friday. Flights in that window arrived on time 94.4% of the time and Friday flights 94.2%, against 91.6% for the route overall.
Set against the rest of the country, this route's record is 14 points better than the US average of 77.6%. That gap is worth roughly 140 fewer late arrivals for every thousand flights.
Key figures
On time
91.6%
Arrivals under 15 minutes late, of 1,185 completed flights
Avg delay
106 min
Across delayed arrivals only, not all flights
Cancelled
0.34%
National rate is 1.81%
Best carrier
SkyWest
92.9% on time across 872 flights
These figures cover 1,189 flights between July 2025 and June 2026. The median arrival is 10 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 IDA to SLC
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 | 872 | 92.9% | 69 min | 0.11% | A+ |
| Delta Air Linesthin sample | 317 | 88.2% | 167 min | 0.95% | A+ |
Flight by flight
Flights on IDA to SLC
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 1,189 flights.
- 5am–8am365 flights89.8%
- 8am–11am2 flights—
- 11am–2pm360 flights94.4%
- 2pm–5pm122 flights94.3%
- 5pm–8pm340 flights89.7%
- 8pm–5am—
Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 94.4% on time. The full set of windows spans 5 points.
Across the year
When delays peak on this route
This route's year swings by 14 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.
November is the best month on the calendar at 100.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. August was the busiest month here, with 122 flights.
Across the week, Friday is the strongest day at 94.2% on time and Sunday the weakest at 89.3%. 5 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 76% of the 10,000 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.
- 76%Carrier
- 15%Extreme weather
- 6%National Airspace System
- 3%Late-arriving aircraft
Extreme weather accounts for 15% 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 2.5 times the usual weather exposure. The split is drawn from 10,446 reported delay minutes.
The largest share of delay minutes, 76%, 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 7,966 of the 10,000 delay minutes reported here.
Cancellations are rare at 0.34%, 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
Badly late arrivals are rare here: only 3.8% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 189 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 runs 89.3% on time across 1,189 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.
The sample behind these figures is 1,189 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 SLC 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 100.0% on time and May 86.4%, a swing of 14 points. If the dates move at all, move them out of May before you think about anything else. 1,185 completed flights over 12 months sit behind that.
Common questions
IDA to SLC questions
How often is IDA to SLC delayed?
About one flight in twelve arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 8.4% of the 1,189 flights in this analysis, against 22.4% nationally. Delayed flights are late by close to two hours on average.
How reliable is IDA to SLC compared with the rest of the country?
91.6% of flights arrive on time here against a national 77.6%, a difference of 14 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on IDA to SLC?
The 11am–2pm departure window is the strongest at 94.4% on time. The 5pm–8pm window is the weakest at 89.7%, 5 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 May delays on IDA to SLC?
May is the weakest month at 86.4% on time, compared with 100.0% in November. Across the year that is 14 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
- SLC to IDA — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- SkyWest Airlines on IDA to SLC92.9%
- Delta Air Lines on IDA to SLC88.2%
- IDA to DEN, a related route79.2%
- DEN to SLC, a related route77.5%
- PHX to SLC, a related route83.0%
- SkyWest Airlines on-time record92.9%
- Delta Air Lines on-time record88.2%
- Worst months to fly in the US, ranked by the data
- Late aircraft, weather, or the airline: what actually causes US flight delays
Direction matters. IDA to SLC and SLC 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.