Flight number record
DL 1553
Delta Air Lines · Salt Lake City to Denver
- Route
- SLC → DEN
- Departs
- 10:15
- Flights
- 324
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1553, check with Delta Air Lines.
DL 1553 lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That rests on 324 flights, with a median arrival 8 minutes early.
Key figures
On time
78.9%
Arrivals under 15 minutes late, of 322 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.31%
National rate is 1.89%
1 hour+ late
4.3%
National rate is 8.3%
These figures cover 324 flights between September 2025 and August 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.
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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 94 of 324 flights, with 10:33 (50 flights) and 09:30 (37 flights) next.
- Departs 10:1594 flights29.0%
- Departs 10:3350 flights15.4%
- Departs 09:3037 flights11.4%
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 10:15 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 1553 runs 5 points worse at 78.9%. 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 1553 next to SLC to DEN
Every carrier on SLC to DEN combined arrived on time 79.0% of the time across 7,709 flights, so DL 1553 is about level with it. Delta flew 1,697 flights on the same city pair under all its flight numbers, including this one, and those ran 79.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1553thin sample | 324 | 78.9% | 45 min | 0.31% | B+ |
| All Delta Air Lines on SLC–DEN | 1,697 | 79.8% | 64 min | 0.18% | B+ |
| All carriers on SLC–DEN | 7,709 | 79.0% | 61 min | 0.51% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1553 quarter by quarter
DL 1553 did not run the same all year. Its best quarter was Jan–Mar 2026 at 84.4% on time and its weakest Jul–Sep 2026 at 67.2%, a swing of 17 points on roughly 65 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 flights76.7%
- Oct–Dec 202588 flights81.8%
- Jan–Mar 202666 flights84.4%
- Apr–Jun 202679 flights81.0%
- Jul–Sep 202661 flights67.2%
Scale runs 60% to 90%.
By weekday, DL 1553 did best on Wednesday at 89.1% on time and worst on Monday at 70.8%. Each day rests on about 46 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1553 runs when it is late
DL 1553 often beats the schedule: 99 of 322 completed flights, 31%, arrived 15 minutes or more early. The 68 late arrivals split 29 under half an hour, 25 between 30 and 60 minutes, and 14 an hour or more.
- 15+ min early99 flights30.7%
- Within 15 min155 flights48.1%
- 15–29 min late29 flights9.0%
- 30–59 min late25 flights7.8%
- 1–2 hours late11 flights3.4%
- 2+ hours late3 flights0.9%
Scale runs 0% to 100%.
Share of 322 completed flights by arrival against schedule.
8 of 50 late departures made up the time and arrived on time, 16% of them. In the other direction, 26 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at DEN.
The worst days
Worst days for DL 1553
The latest arrival of the period was on 3 August 2026, 4 hours 43 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as extreme weather.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 August 2026 | 4 hours 43 minutes | Carrier |
| 27 June 2026 | 3 hours 21 minutes | Extreme weather |
| 22 April 2026 | 2 hours 40 minutes | Extreme weather |
| 17 February 2026 | 1 hour 44 minutes | National Airspace System |
| 24 August 2026 | 1 hour 33 minutes | Extreme weather |
Delay causes
Why DL 1553 runs late
Carrier accounts for 45% of the 3,076 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Carrier
- 31%National Airspace System
- 16%Extreme weather
- 8%Late-arriving aircraft
Extreme weather accounts for 16% 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 2.6 times the usual weather exposure. The split is drawn from 3,076 delay minutes reported on DL 1553.
Cancellations are rare at 0.31%, 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
Badly late arrivals are rare here: only 4.3% land an hour or more behind schedule, against 8.3% 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 (253 flights, 79.2% 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. 324 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DEN to SLCthin sample | 253 | 79.2% | 59 min | 1.19% | B |
What to do with this
Booking DL 1553
For a booking, read DL 1553 as 78.9% on time with 0.31% cancelled over 324 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SLC to DEN, every carrier and departure
- DEN to SLC, the return direction
- Frontier Airlines 3862 on the same route79.6%
- Delta Air Lines 1623 on the same route85.3%
- Delta Air Lines 1586 on the same route68.3%
- SkyWest Airlines 4720 on the same route90.7%
- Delta Air Lines 1667 on the same route79.7%
- SkyWest Airlines 5683 on the same route93.9%
- Salt Lake City International (SLC) delay statistics
- Denver International (DEN) 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.