Carrier route record

DLSLC→BWI

Delta Air Lines · Salt Lake City to Baltimore

Flights: 360
Period: September 2025 to August 2026
Share of route: 47%
Carriers: 2

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on SLC to BWI lands a B, about a point 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 35 minutes on average. That rests on 360 flights, with a median arrival 1 minute late.

The US average over the same twelve months is 77.3%, so there is little to separate Delta on SLC to BWI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

78.3%

Arrivals under 15 minutes late, of 351 completed flights

Avg delay

35 min

Across delayed arrivals only, not all flights

Cancelled

1.94%

National rate is 1.89%

Whole route

81.2%

Every carrier on SLC to BWI, 769 flights

These figures cover 360 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Carrier by carrier

Delta against every carrier on SLC to BWI

Delta flew 360 of the 769 flights on SLC to BWI, about 47% of it. Its 78.3% on time is 3 points worse than the route as a whole, which runs 81.2%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Southwest at 83.6% to Delta at 78.3%.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on SLC to BWI
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	409	83.6%	47 min	1.22%	B
Delta Air Lines (this page)thin sample	360	78.3%	35 min	1.94%	B

Flight by flight

Delta flight numbers on SLC to BWI

DL 207923:4078.3% · 360 flights

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Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 360 flights.

5am–8am—
8am–11am1 flights—
11am–2pm—
2pm–5pm—
5pm–8pm76 flights84.7%
8pm–5am283 flights76.6%

Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is the strongest at 84.7% on time. The full set of windows spans 8 points.

Across the year

Delta on SLC to BWI through the year

Jul–Sep 202530 flights100.0%
Oct–Dec 202587 flights75.3%
Jan–Mar 202690 flights83.7%
Apr–Jun 202691 flights60.0%
Jul–Sep 202662 flights91.7%

Scale runs 50% to 100%.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 78.3% on time across 360 flights.

Delta on SLC to BWI did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Apr–Jun 2026 at 60.0%, a swing of 40 points on roughly 72 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.

Across the week, Saturday is the strongest day at 88.2% on time and Friday the weakest at 64.7%, a spread of 24 points.

Arrival by arrival

How late Delta on SLC to BWI runs when it is late

Most of the lateness is short. 45 of the 76 late arrivals were under half an hour behind, and 8 reached an hour or more.

15+ min early60 flights17.1%
Within 15 min215 flights61.3%
15–29 min late45 flights12.8%
30–59 min late23 flights6.6%
1–2 hours late6 flights1.7%
2+ hours late2 flights0.6%

Scale runs 0% to 100%.

Share of 351 completed flights by arrival against schedule.

A late pushback is often recovered here: of 56 departures that left 15 minutes late or more, 26 still arrived on time. In the other direction, 46 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 BWI.

The worst days

Worst days for Delta on SLC to BWI

The latest arrival of the period was on 15 May 2026, 2 hours 45 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.

The latest arrivals of Delta on SLC to BWI in the period
Date	Arrived late by	Largest filed cause
15 May 2026	2 hours 45 minutes	Carrier
18 February 2026	2 hours 28 minutes	Late-arriving aircraft
30 May 2026	1 hour 52 minutes	Carrier
13 April 2026	1 hour 44 minutes	Carrier
2 January 2026	1 hour 25 minutes	Carrier

Delay causes

Why Delta runs late on this route

National Airspace System accounts for 46% of the 2,683 delay minutes carriers reported here, and the remaining four split what is left.

National Airspace System
46%
Carrier
39%
Late-arriving aircraft
15%

46% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,231 minutes out of 2,683, against a national NAS share of 21%. The split is drawn from 2,683 reported delay minutes.

The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,049 of the 2,683 delay minutes reported here.

Cancellations sit at 1.94% against a national 1.89%, which is ordinary. Diversions add another 0.56%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 2.3% 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.

At 1,865 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 80.2% on time across 360 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 360 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 Delta on SLC to BWI

Put together: treat all of this as provisional. 360 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 78.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 351 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures