Carrier route record
UAIAH→SLC
United Airlines · Houston to Salt Lake City
- Flights
- 879
- Period
- July 2025 to June 2026
- Share of route
- 45%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on IAH to SLC lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 879 flights, with a median arrival 5 minutes early.
Set against the rest of the country, United's IAH to SLC record is 5 points better than the US average of 77.6%. That gap is worth roughly 53 fewer late arrivals for every thousand flights.
Key figures
On time
82.9%
Arrivals under 15 minutes late, of 871 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
0.68%
National rate is 1.81%
Whole route
82.6%
Every carrier on IAH to SLC, 1,957 flights
These figures cover 879 flights between July 2025 and June 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.
Carrier by carrier
United against every carrier on IAH to SLC
United flew 879 of the 1,957 flights on IAH to SLC, about 45% of it. Its 82.9% on time is about level with the route as a whole at 82.6%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 82.9% to SkyWest at 78.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
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 Airlines (this page) | 879 | 82.9% | 64 min | 0.68% | B+ |
| Delta Air Lines | 1,011 | 82.7% | 93 min | 0.30% | B+ |
| SkyWest Airlinesthin sample | 67 | 78.8% | 63 min | 1.49% | B |
Flight by flight
United flight numbers on IAH to SLC
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 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–8am—
- 8am–11am367 flights87.0%
- 11am–2pm130 flights89.2%
- 2pm–5pm19 flights—
- 5pm–8pm—
- 8pm–5am363 flights75.8%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 89.2% on time, ahead of 8pm–5am at 75.8%. 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 8am–11am window is the busiest, with 367 flights scheduled in it.
Across the year
United on IAH to SLC through the year
July is the worst month at 70.5% on time, 22 points below February, the best at 92.3%. 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. January was the busiest month here, with 98 flights.
Across the week, Saturday is the strongest day at 88.4% on time and Monday the weakest at 79.2%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 47% of the 9,540 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.
- 47%Late-arriving aircraft
- 33%Carrier
- 16%National Airspace System
- 4%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 9,540 reported delay minutes here, that single category outweighs weather by 12 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 9,540 reported delay minutes.
Cancellations are rare at 0.68%, 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 costs
5.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 87.5% on time across 878 flights, 5 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 5 points of difference.
One caution: this is a thin sample. 879 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.
What to do with this
Booking United on IAH to SLC
Put together: treat all of this as provisional. 879 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 82.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 871 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to SLC, every carrier
- United on SLC to IAH, the return leg
- Delta Air Lines on IAH to SLC82.7%
- United Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Salt Lake City International (SLC) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.