Route reliability record
IAH→SLC
Houston to Salt Lake City
- Flights
- 1,932
- Period
- September 2025 to August 2026
- Distance
- 1,195 mi
- Carriers
- 3
This route lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 1,932 IAH to SLC flights, of which United Airlines flew 856 at 83.6% on time.
Best time to fly IAH to SLC: a 11am–2pm departure, ideally on a Saturday. Flights in that window arrived on time 87.1% of the time and Saturday flights 87.0%, against 83.4% for the route overall.
Set against the rest of the country, this route's record is 6 points better than the US average of 77.3%. That gap is worth roughly 61 fewer late arrivals for every thousand flights.
Key figures
On time
83.4%
Arrivals under 15 minutes late, of 1,917 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.89%
Best carrier
United
83.6% on time across 856 flights
These figures cover 1,932 flights between September 2025 and August 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.
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Carrier by carrier
Which airline is most reliable on IAH to SLC
The two carriers here are closely matched: half a point 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 856 | 83.6% | 64 min | 0.47% | B+ |
| Delta Air Lines | 1,016 | 83.3% | 90 min | 0.39% | B+ |
| SkyWest Airlinesthin sample | 60 | 79.7% | 67 min | 1.67% | B |
No carrier stands out. United tops the table at 83.6%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on IAH 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.
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Best ways to make this trip
The most reliable ways to fly Houston to Salt Lake City
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. IAH → SLCHouston to Salt Lake City | United Airlines | 83.2% | 83.6% | 0.47% | 11am–2pm, Sat | UA 2242 09:45 |
| 2. IAH → SLCHouston to Salt Lake City | Delta Air Lines | 83.0% | 83.3% | 0.39% | 5am–8am, Tue | DL 1583 07:40 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 10 points, against half a point between the best and worst carrier.
- 5am–8am365 flights86.0%
- 8am–11am363 flights86.7%
- 11am–2pm352 flights87.1%
- 2pm–5pm171 flights82.9%
- 5pm–8pm294 flights80.4%
- 8pm–5am387 flights76.8%
Scale runs 70% to 95%.
The best window here is not the first bank but the 11am–2pm slot at 87.1% on time, ahead of 8pm–5am at 76.8%. 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 387 flights scheduled in it.
Explore
Filter IAH to SLC 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 IAH to SLC, the best departure window is 11am–2pm at 87.1% on time and the worst is 8pm–5am at 76.8%, a wide gap of 10.3 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am86.0%
- 8–11am86.7%
- 11am–2pm87.1%
- 2–5pm82.9%
- 5–8pm80.4%
- 8pm–5am76.8%
best all US flightsScale 60% to 95%.
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.
June is the worst month at 77.5% on time, 14 points below January, the best at 91.1%. 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. March was the busiest month here, with 211 flights.
Across the week, Saturday is the strongest day at 87.0% on time and Sunday the weakest at 79.5%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 46% of the 25,000 delay minutes carriers reported here, and the remaining four split what is left.
- 46%Carrier
- 39%Late-arriving aircraft
- 11%National Airspace System
- 4%Extreme weather
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 25,000 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 24,804 reported delay minutes.
The largest share of delay minutes, 46%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 11,000 of the 25,000 delay minutes reported here.
Cancellations are rare at 0.47%, 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
5.7% 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 1,195 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 runs 86.1% on time across 1,931 flights, within 3 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 1,932 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. January runs 91.1% on time and June 77.5%, a swing of 14 points. If the dates move at all, move them out of June before you think about anything else. 1,917 completed flights over 12 months sit behind that.
Common questions
IAH to SLC questions
How often is IAH to SLC delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.6% of the 1,932 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on IAH to SLC?
United Airlines leads at 83.6% on time across 856 flights. Delta Air Lines is at the other end on 83.3%, a gap of half a point. 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 IAH to SLC?
The 11am–2pm departure window is the strongest at 87.1% on time. The 8pm–5am window is the weakest at 76.8%, 10 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 IAH to SLC?
June is the weakest month at 77.5% on time, compared with 91.1% in January. 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 IAH — the return legseparate record
- George Bush Intercontinental (IAH) delay statistics
- Salt Lake City International (SLC) delay statistics
- United Airlines on IAH to SLC83.6%
- Delta Air Lines on IAH to SLC83.3%
- IAH to ORD, a related route75.1%
- DEN to SLC, a related route78.2%
- IAH to DFW, a related route76.4%
- United Airlines on-time record83.6%
- Delta Air Lines on-time record83.3%
- SkyWest Airlines on-time record79.7%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. IAH to SLC and SLC to IAH 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.