Flight number record

DL 1583

Delta Air Lines · Houston to Salt Lake City

Route: IAH → SLC
Departs: 07:40
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1583, check with Delta Air Lines.

DL 1583 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 365 flights, with a median arrival 8 minutes early.

Set against the rest of the country, DL 1583's record is 7 points better than the US average of 77.6%. That gap is worth roughly 73 fewer late arrivals for every thousand flights.

On time

84.9%

Arrivals under 15 minutes late, of 364 completed flights

Avg delay

114 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

1 hour+ late

6.3%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 8 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.

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 124 of 365 flights, with 07:45 (62 flights) and 07:35 (60 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:40124 flights34.0%
Departs 07:4562 flights17.0%
Departs 07:3560 flights16.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 4 points worse at 84.9%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 1583 next to IAH to SLC

Every carrier on IAH to SLC combined arrived on time 82.6% of the time across 1,957 flights, so DL 1583 is 2 points ahead of it. Delta flew 1,011 flights on the same city pair under all its flight numbers, including this one, and those ran 82.7% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 3 points.

DL 1583 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1583	365	84.9%	114 min	0.27%	B+
All Delta Air Lines on IAH–SLC	1,011	82.7%	93 min	0.30%	B+
All carriers on IAH–SLC	1,957	82.6%	79 min	0.51%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1583 quarter by quarter

Quarter by quarter DL 1583 held fairly steady: 87.0% in Jul–Sep 2025, 82.6% in Oct–Dec 2025, 82.0% in Jan–Mar 2026 and 87.9% in Apr–Jun 2026. A spread of 6 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights87.0%
Oct–Dec 202592 flights82.6%
Jan–Mar 202690 flights82.0%
Apr–Jun 202691 flights87.9%

Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1583 did best on Tuesday at 94.3% on time and worst on Sunday at 72.5%. Each day rests on about 52 flights, so a gap of 22 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1583 runs late

One category carries most of the weight here. Carrier accounts for 78% of the 6,252 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.

Carrier
78%
Late-arriving aircraft
12%
National Airspace System
9%
Extreme weather
1%

The largest share of delay minutes, 78%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 4,858 of the 6,252 delay minutes reported here. The split is drawn from 6,252 delay minutes reported on DL 1583.

Cancellations are rare at 0.27%, 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 routes

What a delay on this flight costs

6.3% 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 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. 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.

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, read DL 1583 as 84.9% on time with 0.27% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures