Flight number record
DL 1583
Delta Air Lines · Houston to Salt Lake City
- Route
- IAH → SLC
- Departs
- 07:40
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1583, check with Delta Air Lines.
DL 1583 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 close to two hours. That rests on 365 flights, with a median arrival 9 minutes early.
Set against the rest of the country, DL 1583's record is 9 points better than the US average of 77.3%. That gap is worth roughly 87 fewer late arrivals for every thousand flights.
Key figures
On time
86.0%
Arrivals under 15 minutes late, of 363 completed flights
Avg delay
109 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
5.2%
National rate is 8.3%
These figures cover 365 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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Schedule
When DL 1583 flies
DL 1583 flies IAH to SLC without a single fixed slot. Its most common scheduled departure was 07:40, used on 103 of 365 flights, with 07:35 (93 flights) and 07:45 (62 flights) next.
- Departs 07:40103 flights28.2%
- Departs 07:3593 flights25.5%
- Departs 07:4562 flights17.0%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 07:40 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1583 runs 3 points worse at 86.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1583 next to IAH to SLC
Every carrier on IAH to SLC combined arrived on time 83.4% of the time across 1,932 flights, so DL 1583 is 3 points ahead of it. Delta flew 1,016 flights on the same city pair under all its flight numbers, including this one, and those ran 83.3% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 5 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1583 | 365 | 86.0% | 109 min | 0.55% | A+ |
| All Delta Air Lines on IAH–SLC | 1,016 | 83.3% | 90 min | 0.39% | B+ |
| All carriers on IAH–SLC | 1,932 | 83.4% | 78 min | 0.47% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1583 quarter by quarter
DL 1583 did not run the same all year. Its best quarter was Jul–Sep 2026 at 93.4% on time and its weakest Jan–Mar 2026 at 82.0%, a swing of 11 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights86.7%
- Oct–Dec 202592 flights82.6%
- Jan–Mar 202690 flights82.0%
- Apr–Jun 202691 flights87.9%
- Jul–Sep 202662 flights93.4%
Scale runs 75% to 100%.
By weekday, DL 1583 did best on Tuesday at 90.4% on time and worst on Sunday at 78.4%. Each day rests on about 52 flights, so a gap of 12 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1583 runs when it is late
DL 1583 often beats the schedule: 130 of 363 completed flights, 36%, arrived 15 minutes or more early. The 51 late arrivals split 22 under half an hour, 10 between 30 and 60 minutes, and 19 an hour or more.
- 15+ min early130 flights35.8%
- Within 15 min182 flights50.1%
- 15–29 min late22 flights6.1%
- 30–59 min late10 flights2.8%
- 1–2 hours late11 flights3.0%
- 2+ hours late8 flights2.2%
Scale runs 0% to 100%.
Share of 363 completed flights by arrival against schedule.
6 of 39 late departures made up the time and arrived on time, 15% of them. 18 flights left on time and still arrived late.
The worst days
Worst days for DL 1583
The latest arrival of the period was on 25 November 2025, 14 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 |
|---|---|---|
| 25 November 2025 | 14 hours 43 minutes | Carrier |
| 12 December 2025 | 13 hours 24 minutes | Carrier |
| 22 November 2025 | 10 hours 37 minutes | Late-arriving aircraft |
| 30 May 2026 | 6 hours 5 minutes | Carrier |
| 19 September 2025 | 5 hours 14 minutes | Late-arriving aircraft |
Delay causes
Why DL 1583 runs late
Carrier accounts for 76% of the 5,554 delay minutes carriers reported here, and the remaining four split what is left.
- 76%Carrier
- 14%Late-arriving aircraft
- 9%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 76%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,199 of the 5,554 delay minutes reported here. The split is drawn from 5,554 delay minutes reported on DL 1583.
Cancellations are rare at 0.55%, 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 routes
What a delay on this flight costs
5.2% 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 close to two hours, 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.
Every one of the 365 flights under DL 1583 in the data flew IAH to SLC. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 365 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 DL 1583
For a booking, DL 1583 has one of the better records a US domestic flight can show: 86.0% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- IAH to SLC, every carrier and departure
- SLC to IAH, the return direction
- United Airlines 2157 on the same route76.9%
- Delta Air Lines 1532 on the same route83.8%
- United Airlines 2242 on the same route86.0%
- George Bush Intercontinental (IAH) delay statistics
- Salt Lake City International (SLC) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.