Route reliability record
SLC→IAH
Salt Lake City to Houston
- Flights
- 1,931
- Period
- September 2025 to August 2026
- Distance
- 1,195 mi
- Carriers
- 3
This route earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 1,931 SLC to IAH flights, of which United Airlines flew 854 at 89.5% on time.
Best time to fly SLC to IAH: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 93.1% of the time and Tuesday flights 89.1%, against 86.1% for the route overall.
Set against the rest of the country, this route's record is 9 points better than the US average of 77.3%. That gap is worth roughly 88 fewer late arrivals for every thousand flights.
Key figures
On time
86.1%
Arrivals under 15 minutes late, of 1,911 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.89%
Best carrier
United
89.5% on time across 854 flights
These figures cover 1,931 flights between September 2025 and August 2026. The median arrival is 9 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 SLC to IAH
The choice of carrier is not cosmetic here. United Airlines arrives on time 89.5% of the time; Delta Air Lines manages 83.1%. Sample sizes sit next to every figure, because a two-point gap across 1,016 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 854 | 89.5% | 79 min | 1.29% | A |
| SkyWest Airlinesthin sample | 61 | 88.1% | 58 min | 1.64% | A |
| Delta Air Lines | 1,016 | 83.1% | 77 min | 0.20% | B+ |
United leads Delta by 6 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on SLC to IAH
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 Salt Lake City to Houston
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. SLC → IAHSalt Lake City to Houston | United Airlines | 88.3% | 89.5% | 1.29% | 5am–8am, Fri | UA 2366 07:00 |
| 2. SLC → IAHSalt Lake City to Houston | Delta Air Lines | 82.9% | 83.1% | 0.20% | 5am–8am, Tue | DL 2502 07:45 |
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 15 points, against 6 points between the best and worst carrier.
- 5am–8am513 flights93.1%
- 8am–11am288 flights88.8%
- 11am–2pm563 flights83.1%
- 2pm–5pm202 flights87.0%
- 5pm–8pm365 flights78.2%
- 8pm–5am—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 78.2% for the evening window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 563 flights scheduled in it.
Explore
Filter SLC to IAH 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 SLC to IAH, the best departure window is 5am–8am at 93.1% on time and the worst is 5pm–8pm at 78.2%, a wide gap of 14.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.1%
- 8–11am88.8%
- 11am–2pm83.1%
- 2–5pm87.0%
- 5–8pm78.2%
- 8pm–5am—
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 1,931 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
June is the worst month at 80.0% on time, 11 points below September, the best at 91.3%. 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, Tuesday is the strongest day at 89.1% on time and Wednesday the weakest at 83.7%, a spread of 5 points.
Delay causes
Why this route gets delayed
Carrier accounts for 54% of the 21,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 22%National Airspace System
- 19%Late-arriving aircraft
- 5%Extreme weather
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 11,000 of the 21,000 delay minutes reported here. The split is drawn from 20,525 reported delay minutes.
Cancellations are rare at 0.73%, 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
Badly late arrivals are rare here: only 4.4% land an hour or more behind schedule, against 8.3% 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.
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 83.4% on time across 1,932 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 1,931 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 IAH after this flight
What to do with this
Booking this route
Put together: avoid the 5pm–8pm departure. It runs 78.2% on time against 93.1% for the 5am–8am slot, and that 15 points is the largest single thing you control here. United Airlines is the strongest operator if the fares are close. 1,911 completed flights over 12 months sit behind that.
Common questions
SLC to IAH questions
How often is SLC to IAH delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.9% of the 1,931 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 SLC to IAH?
United Airlines leads at 89.5% on time across 854 flights. Delta Air Lines is at the other end on 83.1%, a gap of 6 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 SLC to IAH?
The 5am–8am departure window is the strongest at 93.1% on time. The 5pm–8pm window is the weakest at 78.2%, 15 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 SLC to IAH?
June is the weakest month at 80.0% on time, compared with 91.3% in September. Across the year that is 11 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
- IAH to SLC — the return legseparate record
- Salt Lake City International (SLC) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- United Airlines on SLC to IAH89.5%
- Delta Air Lines on SLC to IAH83.1%
- SLC to DEN, a related route79.0%
- ORD to IAH, a related route76.0%
- SLC to PHX, a related route83.5%
- United Airlines on-time record89.5%
- SkyWest Airlines on-time record88.1%
- Delta Air Lines on-time record83.1%
- 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. SLC to IAH and IAH to SLC 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.