Carrier route record
DLIAH→SLC
Delta Air Lines · Houston to Salt Lake City
- Flights
- 1,016
- Period
- September 2025 to August 2026
- Share of route
- 53%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on IAH to SLC 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 an hour and a half on average. That rests on 1,016 flights, with a median arrival 9 minutes early.
Set against the rest of the country, Delta's IAH to SLC record is 6 points better than the US average of 77.3%. That gap is worth roughly 60 fewer late arrivals for every thousand flights.
Key figures
On time
83.3%
Arrivals under 15 minutes late, of 1,008 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
0.39%
National rate is 1.89%
Whole route
83.4%
Every carrier on IAH to SLC, 1,932 flights
These figures cover 1,016 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
Delta against every carrier on IAH to SLC
Delta flew 1,016 of the 1,932 flights on IAH to SLC, most of the route. Its 83.3% on time is about level with the route as a whole at 83.4%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from United at 83.6% to SkyWest at 79.7%. 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 | 856 | 83.6% | 64 min | 0.47% | B+ |
| Delta Air Lines (this page) | 1,016 | 83.3% | 90 min | 0.39% | B+ |
| SkyWest Airlinesthin sample | 60 | 79.7% | 67 min | 1.67% | B |
Flight by flight
Delta flight numbers on IAH to SLC
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Delta runs best on this route
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 1,016 flights.
- 5am–8am365 flights86.0%
- 8am–11am—
- 11am–2pm234 flights84.4%
- 2pm–5pm98 flights81.6%
- 5pm–8pm294 flights80.4%
- 8pm–5am25 flights—
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
The early departures do better, though not dramatically: 86.0% on time for the 5am–8am window against 80.4% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 5am–8am window is the busiest, with 365 flights scheduled in it.
Across the year
Delta on IAH to SLC through the year
December is the weak month at 74.7% on time, against 94.8% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 89 flights.
Across the week, Tuesday is the strongest day at 88.7% on time and Sunday the weakest at 78.2%, a spread of 11 points.
Arrival by arrival
How late Delta on IAH to SLC runs when it is late
Delta on IAH to SLC often beats the schedule: 362 of 1,008 completed flights, 36%, arrived 15 minutes or more early. The 168 late arrivals split 59 under half an hour, 47 between 30 and 60 minutes, and 62 an hour or more.
- 15+ min early362 flights35.9%
- Within 15 min478 flights47.4%
- 15–29 min late59 flights5.9%
- 30–59 min late47 flights4.7%
- 1–2 hours late37 flights3.7%
- 2+ hours late25 flights2.5%
Scale runs 0% to 100%.
Share of 1,008 completed flights by arrival against schedule.
43 of 173 late departures made up the time and arrived on time, 25% of them. 38 flights left on time and still arrived late.
The worst days
Worst days for Delta on IAH to SLC
The latest arrival of the period was on 30 March 2026, 15 hours behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 March 2026 | 15 hours | Carrier |
| 25 November 2025 | 14 hours 43 minutes | Carrier |
| 8 March 2026 | 13 hours 44 minutes | Carrier |
| 12 December 2025 | 13 hours 24 minutes | Carrier |
| 2 June 2026 | 13 hours 19 minutes | Carrier |
Delay causes
Why Delta runs late on this route
Carrier accounts for 55% of the 15,000 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Carrier
- 33%Late-arriving aircraft
- 9%National Airspace System
- 4%Extreme weather
The largest share of delay minutes, 55%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 8,320 of the 15,000 delay minutes reported here. The split is drawn from 15,146 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.0% on time here.
Cancellations are rare at 0.39%, 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 costs
6.2% 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 an hour and a half, 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 83.1% on time across 1,016 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 1,016 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 Delta on IAH to SLC
Put together: treat all of this as provisional. 1,016 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 83.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,008 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to SLC, every carrier
- Delta on SLC to IAH, the return leg
- United Airlines on IAH to SLC83.6%
- Delta Air Lines 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
- Worst months to fly in the US, ranked by the data
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.