Flight number record

DL 1553

Delta Air Lines · Salt Lake City to Denver

Route: SLC → DEN
Departs: 10:15
Flights: 325
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1553, check with Delta Air Lines.

DL 1553 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 45 minutes on average. That is a workable record, not a spotless one. That rests on 325 flights, with a median arrival 10 minutes early.

Set against the rest of the country, DL 1553's record is 5 points better than the US average of 77.6%. That gap is worth roughly 48 fewer late arrivals for every thousand flights.

On time

82.4%

Arrivals under 15 minutes late, of 323 completed flights

Avg delay

46 min

Across delayed arrivals only, not all flights

Cancelled

0.31%

National rate is 1.81%

1 hour+ late

4.0%

National rate is 8.1%

These figures cover 325 flights between July 2025 and June 2026. The median arrival is 10 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 1553 flies

DL 1553 flies SLC to DEN without a single fixed slot. Its most common scheduled departure was 10:15, used on 79 of 325 flights, with 10:20 (41 flights) and 09:30 (37 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 10:1579 flights24.3%
Departs 10:2041 flights12.6%
Departs 09:3037 flights11.4%

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 10:15 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 1553 runs level with that at 82.4%. 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 1553 next to SLC to DEN

Every carrier on SLC to DEN combined arrived on time 77.8% of the time across 7,757 flights, so DL 1553 is 5 points ahead of it. Delta flew 1,690 flights on the same city pair under all its flight numbers, including this one, and those ran 79.4% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.

DL 1553 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1553thin sample	325	82.4%	46 min	0.31%	B+
All Delta Air Lines on SLC–DEN	1,690	79.4%	64 min	0.24%	B+
All carriers on SLC–DEN	7,757	77.8%	61 min	0.55%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1553 quarter by quarter

Quarter by quarter DL 1553 held fairly steady: 82.6% in Jul–Sep 2025, 81.8% in Oct–Dec 2025, 84.4% in Jan–Mar 2026 and 81.0% in Apr–Jun 2026. A spread of 3 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights82.6%
Oct–Dec 202588 flights81.8%
Jan–Mar 202666 flights84.4%
Apr–Jun 202679 flights81.0%

Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1553 did best on Wednesday at 91.3% on time and worst on Friday at 72.7%. Each day rests on about 46 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1553 runs late

One category carries most of the weight here. Carrier accounts for 48% of the 2,595 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
48%
National Airspace System
28%
Extreme weather
14%
Late-arriving aircraft
10%

Extreme weather accounts for 14% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.2 times the usual weather exposure. The split is drawn from 2,595 delay minutes reported on DL 1553.

Cancellations are rare at 0.31%, 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

Badly late arrivals are rare here: only 4.0% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

DL 1553 is not only a SLC to DEN flight. It also flew DEN to SLC (254 flights, 81.7% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.

One caution: this is a thin sample. 325 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.

Other routes flown as DL 1553
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
DEN to SLCthin sample	254	81.7%	49 min	1.18%	B

What to do with this

Booking DL 1553

For a booking, read DL 1553 as 82.4% on time with 0.31% cancelled over 325 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