Flight number record

DL 2455

Delta Air Lines · Salt Lake City to St. Louis

Route: SLC → STL
Departs: 09:35
Flights: 295
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 77.6%. When something does go wrong the average delay runs about an hour. That rests on 295 flights, with a median arrival 12 minutes early.

Set against the rest of the country, DL 2455's record is 13 points better than the US average of 77.6%. That gap is worth roughly 128 fewer late arrivals for every thousand flights.

On time

90.4%

Arrivals under 15 minutes late, of 292 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

1 hour+ late

2.7%

National rate is 8.1%

These figures cover 295 flights between July 2025 and June 2026. The median arrival is 12 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 2455 flies

DL 2455 flies SLC to STL without a single fixed slot. Its most common scheduled departure was 09:35, used on 80 of 295 flights, with 09:40 (71 flights) and 09:48 (34 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 09:3580 flights27.1%
Departs 09:4071 flights24.1%
Departs 09:4834 flights11.5%

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 09:35 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 2455 runs 6 points better at 90.4%. 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 2455 next to SLC to STL

Every carrier on SLC to STL combined arrived on time 83.9% of the time across 989 flights, so DL 2455 is 7 points ahead of it. Delta flew 978 flights on the same city pair under all its flight numbers, including this one, and those ran 83.8% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 9 points.

DL 2455 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 2455thin sample	295	90.4%	61 min	0.00%	A+
All Delta Air Lines on SLC–STL	978	83.8%	63 min	0.51%	B+
All carriers on SLC–STL	989	83.9%	63 min	0.51%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 2455 quarter by quarter

Quarter by quarter DL 2455 held fairly steady: 85.6% in Jul–Sep 2025, 91.2% in Oct–Dec 2025 and 93.0% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202590 flights85.6%
Oct–Dec 202591 flights91.2%
Jan–Mar 202625 flights—
Apr–Jun 202689 flights93.0%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 2455 did best on Friday at 95.3% on time and worst on Monday at 83.3%. Each day rests on about 42 flights, so a gap of 12 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 2455 runs late

One category carries most of the weight here. Carrier accounts for 57% of the 1,695 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
57%
Late-arriving aircraft
28%
National Airspace System
11%
Extreme weather
3%

The largest share of delay minutes, 57%, 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 972 of the 1,695 delay minutes reported here. The split is drawn from 1,695 delay minutes reported on DL 2455.

Cancellations are rare at 0.00%, below the national 1.81% 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 2.7% 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.

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. 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.

DL 2455 is not only a SLC to STL flight. It also flew STL to SLC (257 flights, 88.7% 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. 295 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 2455
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
STL to SLCthin sample	257	88.7%	75 min	0.00%	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: 90.4% on time and 0.00% cancelled. That is a base rate, not a promise about any single 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