Flight number record
DL 2455
Delta Air Lines · Salt Lake City to St. Louis
- Route
- SLC → STL
- Departs
- 09:40
- Flights
- 297
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 2455, check with Delta Air Lines.
DL 2455 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 45 minutes. That rests on 297 flights, with a median arrival 10 minutes early.
Set against the rest of the country, DL 2455's record is 13 points better than the US average of 77.3%. That gap is worth roughly 125 fewer late arrivals for every thousand flights.
Key figures
On time
89.8%
Arrivals under 15 minutes late, of 294 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
2.4%
National rate is 8.3%
These figures cover 297 flights between September 2025 and August 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.
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Schedule
When DL 2455 flies
DL 2455 flies SLC to STL without a single fixed slot. Its most common scheduled departure was 09:40, used on 84 of 297 flights, with 09:35 (39 flights) and 09:41 (34 flights) next.
- Departs 09:4084 flights28.3%
- Departs 09:3539 flights13.1%
- Departs 09:4134 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 09:40 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 2455 runs 6 points better at 89.8%. 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 2455 next to SLC to STL
Every carrier on SLC to STL combined arrived on time 83.7% of the time across 990 flights, so DL 2455 is 6 points ahead of it. Delta flew 981 flights on the same city pair under all its flight numbers, including this one, and those ran 83.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 9 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2455thin sample | 297 | 89.8% | 45 min | 0.00% | A+ |
| All Delta Air Lines on SLC–STL | 981 | 83.7% | 58 min | 0.61% | B+ |
| All carriers on SLC–STL | 990 | 83.7% | 58 min | 0.61% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 2455 quarter by quarter
DL 2455 did not run the same all year. Its best quarter was Apr–Jun 2026 at 93.0% on time and its weakest Jul–Sep 2025 at 80.0%, a swing of 13 points on roughly 74 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 flights80.0%
- Oct–Dec 202591 flights91.2%
- Jan–Mar 202625 flights—
- Apr–Jun 202689 flights93.0%
- Jul–Sep 202662 flights85.5%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2455 did best on Tuesday at 95.3% on time and worst on Monday at 81.4%. Each day rests on about 42 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 2455 runs when it is late
DL 2455 often beats the schedule: 108 of 294 completed flights, 37%, arrived 15 minutes or more early. The 30 late arrivals split 10 under half an hour, 13 between 30 and 60 minutes, and 7 an hour or more. Not one arrived two hours late.
- 15+ min early108 flights36.7%
- Within 15 min156 flights53.1%
- 15–29 min late10 flights3.4%
- 30–59 min late13 flights4.4%
- 1–2 hours late7 flights2.4%
- 2+ hours late0 flights0.0%
Scale runs 0% to 100%.
Share of 294 completed flights by arrival against schedule.
6 of 31 late departures made up the time and arrived on time, 19% of them. Only 5 left on time and still arrived late.
The worst days
Worst days for DL 2455
The latest arrival of the period was on 1 December 2025, 1 hour 45 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 December 2025 | 1 hour 45 minutes | National Airspace System |
| 30 December 2025 | 1 hour 32 minutes | Carrier |
| 1 August 2026 | 1 hour 25 minutes | Carrier |
| 16 August 2026 | 1 hour 25 minutes | Carrier |
| 9 March 2026 | 1 hour 18 minutes | Carrier |
Delay causes
Why DL 2455 runs late
Carrier accounts for 73% of the 1,362 delay minutes carriers reported here, and the remaining four split what is left.
- 73%Carrier
- 17%National Airspace System
- 6%Late-arriving aircraft
- 3%Extreme weather
The largest share of delay minutes, 73%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 995 of the 1,362 delay minutes reported here. The split is drawn from 1,362 delay minutes reported on DL 2455.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are 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 2.4% 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.
The 1,156 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.
DL 2455 is not only a SLC to STL flight. It also flew STL to SLC (261 flights, 88.4% 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. 297 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 |
|---|---|---|---|---|---|
| STL to SLCthin sample | 261 | 88.4% | 72 min | 0.38% | A+ |
What to do with this
Booking DL 2455
For a booking, DL 2455 has one of the better records a US domestic flight can show: 89.8% on time and 0.00% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- SLC to STL, every carrier and departure
- STL to SLC, the return direction
- Delta Air Lines 2666 on the same route79.8%
- Salt Lake City International (SLC) delay statistics
- St. Louis Lambert International (STL) 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.