Carrier route record
DLSLC→IAH
Delta Air Lines · Salt Lake City to Houston
- 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 SLC to IAH 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 1,016 flights, with a median arrival 7 minutes early.
Set against the rest of the country, Delta's SLC to IAH record is 6 points better than the US average of 77.3%. That gap is worth roughly 58 fewer late arrivals for every thousand flights.
Key figures
On time
83.1%
Arrivals under 15 minutes late, of 1,012 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
0.20%
National rate is 1.89%
Whole route
86.1%
Every carrier on SLC to IAH, 1,931 flights
These figures cover 1,016 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
Delta against every carrier on SLC to IAH
Delta flew 1,016 of the 1,931 flights on SLC to IAH, most of the route. Its 83.1% on time is 3 points worse than the route as a whole, which runs 86.1%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 89.5% to Delta at 83.1%. 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 | 854 | 89.5% | 79 min | 1.29% | A |
| SkyWest Airlinesthin sample | 61 | 88.1% | 58 min | 1.64% | A |
| Delta Air Lines (this page) | 1,016 | 83.1% | 77 min | 0.20% | B+ |
Flight by flight
Delta flight numbers on SLC to IAH
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 matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against half a point between the best and worst carrier.
- 5am–8am145 flights89.6%
- 8am–11am220 flights88.2%
- 11am–2pm201 flights81.5%
- 2pm–5pm85 flights83.5%
- 5pm–8pm365 flights78.2%
- 8pm–5am—
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.6% of the time, against 78.2% for the evening window. That is 11 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 365 flights scheduled in it.
Across the year
Delta on SLC to IAH through the year
July is the worst month at 76.4% on time, 13 points below September, the best at 89.6%. 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 89 flights.
Across the week, Tuesday is the strongest day at 87.5% on time and Thursday the weakest at 80.7%, a spread of 7 points.
Arrival by arrival
How late Delta on SLC to IAH runs when it is late
Delta on SLC to IAH often beats the schedule: 286 of 1,012 completed flights, 28%, arrived 15 minutes or more early. The 171 late arrivals split 70 under half an hour, 49 between 30 and 60 minutes, and 52 an hour or more.
- 15+ min early286 flights28.3%
- Within 15 min555 flights54.8%
- 15–29 min late70 flights6.9%
- 30–59 min late49 flights4.8%
- 1–2 hours late23 flights2.3%
- 2+ hours late29 flights2.9%
Scale runs 0% to 100%.
Share of 1,012 completed flights by arrival against schedule.
30 of 161 late departures made up the time and arrived on time, 19% of them. 40 flights left on time and still arrived late.
The worst days
Worst days for Delta on SLC to IAH
The latest arrival of the period was on 21 November 2025, 18 hours 43 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 21 November 2025 | 18 hours 43 minutes | Carrier |
| 12 November 2025 | 15 hours 5 minutes | Carrier |
| 10 May 2026 | 14 hours 21 minutes | Extreme weather |
| 18 September 2025 | 14 hours 19 minutes | Carrier |
| 12 April 2026 | 4 hours 56 minutes | National Airspace System |
Delay causes
Why Delta runs late on this route
Carrier accounts for 60% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 60%Carrier
- 18%National Airspace System
- 15%Late-arriving aircraft
- 8%Extreme weather
The largest share of delay minutes, 60%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 7,913 of the 13,000 delay minutes reported here. The split is drawn from 13,217 reported delay minutes.
Cancellations are rare at 0.20%, 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
5.1% 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 83.3% 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 SLC to IAH
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 83.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,012 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to IAH, every carrier
- Delta on IAH to SLC, the return leg
- United Airlines on SLC to IAH89.5%
- Delta Air Lines network-wide record
- Salt Lake City International (SLC) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- 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
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.